Queue UI requests from page fragments while app in background

> As of now, note that this will create silent bugs.

for that, there could be a enqueing for the webview reload request (which is what calls `congratsInfo`) to run when the lifecycle is at least `onStart`. If there is more than one request, ignore the older ones

_Originally posted by @BrayanDSO in https://github.com/ankidroid/Anki-Android/issues/15690#issuecomment-1967596903_