Refactor `FlutterDevice.connect` and VM service discovery (#191221)

## Description

Refactors `FlutterDevice.connect` in `packages/flutter_tools` to accept
a single resolved `Uri` instead of a `Stream<Uri>`.

- Replaces `FlutterDevice.vmServiceUris` with `Future<Uri>?
vmServiceUri`.
- Eliminates stream subscription, `_isListeningForVmServiceUri`, and
stream state management from `resident_runner.dart`.
- Moves single VM service candidate resolution into
`VMServiceDiscoveryForAttach.firstValidUri` and
`AttachCommand._discoverVmService`.
- Updates `attach.dart`, `run_cold.dart`, `run_hot.dart`, and associated
test suites.

## Tests
- `packages/flutter_tools/test/commands.shard/hermetic/attach_test.dart`
- `packages/flutter_tools/test/general.shard/cold_test.dart`
-
`packages/flutter_tools/test/general.shard/device_vm_service_discovery_for_attach_test.dart`
- `packages/flutter_tools/test/general.shard/resident_runner_test.dart`
-
`packages/flutter_tools/test/general.shard/resident_web_runner_test.dart`
- `packages/flutter_tools/test/general.shard/run_hot_test.dart`
-
`packages/flutter_tools/test/general.shard/proxied_devices/proxied_devices_test.dart`