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/ts/metadata/lifecycle_hooks_spec.ts

@@ -106,8 +106,9 @@ import {TestBed} from '@angular/core/testing';
       // #docregion OnChanges
       @Component({selector: 'my-cmp', template: `...`})
       class MyComponent implements OnChanges {
+        // TODO(issue/24571): remove '!'.
         @Input()
-        prop: number;
+        prop !: number;
 
         ngOnChanges(changes: SimpleChanges) {
           // changes.prop contains the old and the new value...