[devtools+wasm] Feature flag that enables for a Flutter/Dart channel, instead of boolean #9438
Description
Currently we only support developing features behind a boolean (enabled / not enabled) flag. Historically we have enabled the flag before the stable release we would like the feature to go out with, giving us time to fix any issues on beta.
For the DevTools on wasm experiment, it would be nice to enable on beta over multiple release cycles.
From the DevTools+wasm readiness assessment doc:
"We haven’t done this before, but technically I believe we could enable the experiment only for Flutter beta branches. That means that any user on Flutter beta both before and after Flutter 3.38 stable release would be opted into the experiment by default."