GetGuid noexcept Fix (#3806)

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## Summary of the Pull Request
Fixed the noexcept specifier on `GetGuid`, and corrected `FindProfile` and `FindGuid` so they don't throw. Also, adjusted `SettingsTests` to reflect these changes.

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## References

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## PR Checklist
* [x] Closes #3763
* [x] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [x] Tests added/passed updated a test group in `SettingsTests`
* [ ] Requires documentation to be updated
* [x] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #3763

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## Detailed Description of the Pull Request / Additional comments
The `noexcept` specifier on `GetGuid` was not removed when `Profile` was [updated](https://github.com/microsoft/terminal/issues/3763#issuecomment-559497094) to `std::optional<GUID>`. This PR fixes that and modifies two helper functions `FindProfile` and `FindGuid` in `CascadiaSettings` to work correctly if `GetGuid` does throw. 

<!-- Describe how you validated the behavior. Add automated tests wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
Updated the `TestHelperFunctions` test group in `SettingsTests` and made sure the tests pass.

src/cascadia/LocalTests_TerminalApp/SettingsTests.cpp

@@ -1280,11 +1280,11 @@ namespace TerminalAppLocalTests
                     "guid": "{6239a42c-6666-49a3-80bd-e8fdd045185c}"
                 },
                 {
-                    "name" : "Ubuntu",
+                    "name" : "ThisProfileShouldNotThrow"
-                    "guid" : "{2C4DE342-38B7-51CF-B940-2309A097F518}"
                 },
                 {
-                    "name" : "ThisProfileShouldNotCrash"
+                    "name" : "Ubuntu",
+                    "guid" : "{2C4DE342-38B7-51CF-B940-2309A097F518}"
                 }
             ]
         })" };
@@ -1292,11 +1292,13 @@ namespace TerminalAppLocalTests
         auto name0{ L"profile0" };
         auto name1{ L"profile1" };
         auto name2{ L"Ubuntu" };
+        auto name3{ L"ThisProfileShouldNotThrow" };
         auto badName{ L"DoesNotExist" };
 
         auto guid0{ Microsoft::Console::Utils::GuidFromString(L"{6239a42c-5555-49a3-80bd-e8fdd045185c}") };
         auto guid1{ Microsoft::Console::Utils::GuidFromString(L"{6239a42c-6666-49a3-80bd-e8fdd045185c}") };
         auto guid2{ Microsoft::Console::Utils::GuidFromString(L"{2C4DE342-38B7-51CF-B940-2309A097F518}") };
+        auto fakeGuid{ Microsoft::Console::Utils::GuidFromString(L"{FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF}") };
         std::optional<GUID> badGuid{};
 
         VerifyParseSucceeded(settings0String);
@@ -1308,22 +1310,19 @@ namespace TerminalAppLocalTests
         VERIFY_ARE_EQUAL(guid0, settings.FindGuid(name0));
         VERIFY_ARE_EQUAL(guid1, settings.FindGuid(name1));
         VERIFY_ARE_EQUAL(guid2, settings.FindGuid(name2));
+        VERIFY_ARE_EQUAL(badGuid, settings.FindGuid(name3));
         VERIFY_ARE_EQUAL(badGuid, settings.FindGuid(badName));
-        // Following test will fail because GetGuid throws (despite being noexcept)
-        // VERIFY_ARE_EQUAL(badGuid, settings.FindGuid(L"ThisProfileShouldNotCrash"));
 
-        // Following lines only work because the GUID-less profile is last
         auto prof0{ settings.FindProfile(guid0) };
         auto prof1{ settings.FindProfile(guid1) };
         auto prof2{ settings.FindProfile(guid2) };
-        // Following line will fail because GetGuid throws (despite being noexcept)
+
-        // auto badProf{ settings.FindProfile(badGuid) };
+        auto badProf{ settings.FindProfile(fakeGuid) };
+        VERIFY_ARE_EQUAL(badProf, nullptr);
 
         VERIFY_ARE_EQUAL(name0, prof0->GetName());
         VERIFY_ARE_EQUAL(name1, prof1->GetName());
         VERIFY_ARE_EQUAL(name2, prof2->GetName());
-        // Following test will fail because GetGuid throws (despite being noexcept)
-        // VERIFY_ARE_EQUAL(badName, badProf->GetName());
     }
 
     void SettingsTests::TestLayerGlobalsOnRoot()

src/cascadia/TerminalApp/CascadiaSettings.cpp

@@ -78,7 +78,12 @@ std::optional<GUID> CascadiaSettings::FindGuid(const std::wstring& profileName)
     {
         if (profileName == profile.GetName())
         {
-            profileGuid = profile.GetGuid();
+            try
+            {
+                profileGuid = profile.GetGuid();
+            }
+            CATCH_LOG();
+
             break;
         }
     }
@@ -98,10 +103,14 @@ const Profile* CascadiaSettings::FindProfile(GUID profileGuid) const noexcept
 {
     for (auto& profile : _profiles)
     {
-        if (profile.GetGuid() == profileGuid)
+        try
         {
-            return &profile;
+            if (profile.GetGuid() == profileGuid)
+            {
+                return &profile;
+            }
         }
+        CATCH_LOG();
     }
     return nullptr;
 }

src/cascadia/TerminalApp/Profile.cpp

@@ -138,7 +138,7 @@ bool Profile::HasSource() const noexcept
     return _source.has_value();
 }
 
-GUID Profile::GetGuid() const noexcept
+GUID Profile::GetGuid() const
 {
     // This can throw if we never had our guid set to a legitimate value.
     THROW_HR_IF_MSG(E_FAIL, !_guid.has_value(), "Profile._guid always expected to have a value");

src/cascadia/TerminalApp/Profile.h

@@ -64,7 +64,7 @@ public:
 
     bool HasGuid() const noexcept;
     bool HasSource() const noexcept;
-    GUID GetGuid() const noexcept;
+    GUID GetGuid() const;
     void SetSource(std::wstring_view sourceNamespace) noexcept;
     std::wstring_view GetName() const noexcept;
     bool HasConnectionType() const noexcept;