fix(ivy): use the imported name of decorators for detection (#29061)

Currently, ngtsc has a bug where if you alias the name of a decorator when
importing it, it won't be detected properly. This is because the compiler
uses the aliased name and not the original, declared name of the decorator
for detection.

This commit fixes the compiler to compare against the declared name of
decorators when available, and adds a test to prevent regression.

PR Close #29061

packages/compiler-cli/test/ngtsc/ngtsc_spec.ts

@@ -160,6 +160,24 @@ describe('ngtsc behavioral tests', () => {
     expect(dtsContents).toContain('static ngInjectableDef: i0.ɵInjectableDef<Service>;');
   });
 
+  it('should compile @Injectable with an @Optional dependency', () => {
+    env.tsconfig();
+    env.write('test.ts', `
+      import {Injectable, Optional as Opt} from '@angular/core';
+
+      @Injectable()
+      class Dep {}
+
+      @Injectable()
+      class Service {
+        constructor(@Opt() dep: Dep) {}
+      }
+    `);
+    env.driveMain();
+    const jsContents = env.getContents('test.js');
+    expect(jsContents).toContain('inject(Dep, 8)');
+  });
+
   it('should compile Components (inline template) without errors', () => {
     env.tsconfig();
     env.write('test.ts', `