web: revert DynamicallyImportedMonacoSettingsEditor change in #36033
Created by: LawnGnome
This change broke the detection of the editor being ready, which in turn broke quick actions in the settings toolbar.
A clean revert doesn't quite work, since TypeScript is now smart enough to figure out that MonacoSettingsEditor is always defined. Looking at the (only) caller of monacoRef, I think we're safe to just remove that check completely and rely on the value of this.monaco. It doesn't break anything in practice.
Fixes #36329 (closed).
Test plan
Manual testing on the code host editor page.
App preview:
Check out the client app preview documentation to learn more.