fix(ivy): ngcc - render namespaced imported decorators correctly (#31426)

The support for decorators that were imported via a namespace,
e.g. `import * as core from `@angular/core` was implemented
piecemeal. This meant that it was easy to miss situations where
a decorator identifier needed to be handled as a namepsaced
import rather than a direct import.

One such issue was that UMD processing of decorators was not
correct: the namespace was being omitted from references to
decorators.

Now the types have been modified to make it clear that a
`Decorator.identifier` could hold a namespaced identifier,
and the corresponding code that uses these types has been
fixed.

Fixes #31394

PR Close #31426

packages/compiler-cli/src/ngtsc/annotations/src/metadata.ts

@@ -124,7 +124,7 @@ function classMemberToMetadata(
 function decoratorToMetadata(decorator: Decorator): ts.ObjectLiteralExpression {
   // Decorators have a type.
   const properties: ts.ObjectLiteralElementLike[] = [
-    ts.createPropertyAssignment('type', ts.updateIdentifier(decorator.identifier)),
+    ts.createPropertyAssignment('type', ts.getMutableClone(decorator.identifier)),
   ];
   // Sometimes they have arguments.
   if (decorator.args !== null && decorator.args.length > 0) {

packages/compiler-cli/src/ngtsc/annotations/test/metadata_spec.ts

@@ -26,6 +26,16 @@ runInEachFileSystem(() => {
           `/*@__PURE__*/ i0.ɵsetClassMetadata(Target, [{ type: Component, args: ['metadata'] }], null, null);`);
     });
 
+    it('should convert namespaced decorated class metadata', () => {
+      const res = compileAndPrint(`
+    import * as core from '@angular/core';
+
+    @core.Component('metadata') class Target {}
+    `);
+      expect(res).toEqual(
+          `/*@__PURE__*/ i0.ɵsetClassMetadata(Target, [{ type: core.Component, args: ['metadata'] }], null, null);`);
+    });
+
     it('should convert decorated class constructor parameter metadata', () => {
       const res = compileAndPrint(`
     import {Component, Inject, Injector} from '@angular/core';