[flutter_tools] Remove unused parameter when connected DAP to VM Service (#108285)

Since https://github.com/dart-lang/sdk/commit/02d9c3e6a586ad47909262931375f25abb34b4e3 this flag does absolutely nothing. The behaviour it controlled is now automatic and the flag is not required.

The flag will be removed from the Dart SDK in the future after Flutter is no longer using it.