Add test case for isolated declarations function expression issue

Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

tests/cases/compiler/isolatedDeclarationsFunctionExpressionInCall.ts

@@ -0,0 +1,21 @@
+// @isolatedDeclarations: true
+// @declaration: true
+
+declare function observer<T>(fn: T): T;
+declare function action<T>(fn: T): T;
+
+export const Component = observer(() => {
+  return "hello";
+});
+
+export const thing = action(function () {
+  return Component;
+});
+
+export const arrowWithType = observer((): string => {
+  return "typed";
+});
+
+export const functionWithType = action(function (): typeof Component {
+  return Component;
+});