moveToNewFile: Fix bug for missing importClause (#24224)

src/services/refactors/moveToNewFile.ts

@@ -440,6 +440,7 @@ namespace ts.refactor {
         switch (i.kind) {
             case SyntaxKind.ImportDeclaration: {
                 const clause = i.importClause;
+                if (!clause) return undefined;
                 const defaultImport = clause.name && keep(clause.name) ? clause.name : undefined;
                 const namedBindings = clause.namedBindings && filterNamedBindings(clause.namedBindings, keep);
                 return defaultImport || namedBindings

tests/cases/fourslash/moveToNewFile.ts

@@ -1,6 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: /a.ts
+////import "./foo";
 ////import { a, b, alreadyUnused } from "./other";
 ////const p = 0;
 ////[|const y = p + b;|]
@@ -11,6 +12,7 @@ verify.moveToNewFile({
         "/a.ts":
 `import { y } from "./y";
 
+import "./foo";
 import { a, alreadyUnused } from "./other";
 export const p = 0;
 a; y;`,