fix(Compiler): In the DI compiler, check for `package:`-potential  URLs first.
fix(Compiler): In the DI compiler, check for `package:`-potential  URLs first.

This prevents accidentally linking to an `asset` URL, which is invalid code,
when the `asset:` URL is linking to `lib/`; that means we can just use a simple
`package:` URL to point to it:
  asset:foo/lib/foo.dart ===
  package:foo/foo.dart

PiperOrigin-RevId: 181680139

kevmoo/angular,chalin/angular2,kevmoo/angular,angulardart/angular,angulardart/angular,matanlurey/angular,chalin/angular2,kevmoo/angular,angulardart/angular,chalin/angular2,matanlurey/angular,matanlurey/angular