Migrate _web packages to package:web, etc to support Wasm

[kevmoo]

We are working on public documentation for this process, but creating this issue as a placeholder.

The short version:

• Migrate usage of dart:html to package:web
• Migrate usage of dart:js, dart:js_util, and package:js to dart:js_interop

[IchordeDionysos]

@Lyokone could we add a checklist of things that need to be done aka. packages that still need to be migrated to a TODO list in this issue?

e.g., Remote Config and Performance Monitoring, ... are also still open but have no PR yet.
And at the end, as I understand it, we'd have to remove js from all packages?!

[The-RootCause]

@Lyokone Thank you.
Is there a any projection when the plugin can be compatible with Wasm ?
The current plugin is not compatible yet with wasm, which is blocking all firebase related plugins from being compatible with wasm,

[IchordeDionysos]

Related issue: #12466

[MominRaza]

web_plugin_registrant.dart => package:firebase_app_check_web => dart:html
App check is still using dart:html

[kevmoo]

web_plugin_registrant.dart => package:firebase_app_check_web => dart:html
App check is still using dart:html

Thanks @MominRaza ! See #12597

[kevmoo]

We can close this out now, right @MominRaza ?

[MominRaza]

Now I'm able to build with --wasm, yes now you can close this issue.
Thanks

[kevmoo]

Well done, folks!