flutter-tool: enum cleanup

[web] stop using deprecated jsonwire web-driver protocol

This reverts commit 275ab9c6.

Revert "Reland "Remove references to Observatory (#118577)""

This reverts commit 298d8c76.

This reverts commit 2df140f4.

Observatory is being deprecated for Dart 3.0 so it should no longer be
referenced in tooling messaging / flags.

See https://github.com/dart-lang/sdk/issues/50233

* dart fix --apply

* manual fixes

* fix after merge conflicts

* review

* Migrate packages/flutter_tools/test/general.shard, part 1/2

* Fix most of the tests

* Fix analysis

* Fix analysis

* Fix test

* Fix analysis

* Fix analysis

* Fix nit

This reverts commit 5fd259be.

* [web] use resident resident runner in flutter drive

* Add link to documentation in error message

The current WebDriver message is incomplete. Add link to
the documentation on WebDrivers for different browsers
to help troubleshooting.

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

This reverts commit a90880a8.