ConstantReader.revive cannot revive constant fields with a type not defined in the same library as the field

For instance trying to revive from

```dart
@Foo.foo
class Foo {
static const foo = Deprecated('argument');
}
```

When we search for potential fields which define this argument, we only search the library that defines `Deprecated`), and of course never find a field equal to our object.

https://github.com/dart-lang/source_gen/blob/4dc8f1f9f51f9126aa50bad1736249bc3d8a0623/source_gen/lib/src/constants/revive.dart#L68

If we could know to search the library defining `Foo` we'd find it.

Inspect source_gen/lib/src/constants/revive.dart around line 68 and reproduce the example where Deprecated is defined in a different library from Foo. Trace how potential fields are selected; done means ConstantReader.revive finds Foo.foo across library boundaries and revives the constant value.

Written by the indexing model from the issue text.