Enable disposable tracking

[jrieken]

With #236487 I have added a disposable tracker that uses the finalization registry. The logic is that a GC'ed disposable that hasn't been disposed is a bug that we need to fix.

This should be enabled by default when running out of dev but before that we need to mark a couple of disposables as singletons, e.g those returned from registries (menu, command, language, editors etc...)