build(bazel): Turning on strictPropertyInitialization for Angular. (#24572)

All errors for existing fields have been detected and suppressed with a
`!` assertion.

Issue/24571 is tracking proper clean up of those instances.

One-line change required in ivy/compilation.ts, because it appears that
the new syntax causes tsickle emitted node to no longer track their
original sourceFiles.

PR Close #24572

packages/examples/core/animation/ts/dsl/animation_example.ts

@@ -43,7 +43,8 @@ import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
   `
 })
 export class MyExpandoCmp {
-  stateExpression: string;
+  // TODO(issue/24571): remove '!'.
+  stateExpression !: string;
   constructor() { this.collapse(); }
   expand() { this.stateExpression = 'expanded'; }
   collapse() { this.stateExpression = 'collapsed'; }