Regression: window maximization warning cannot be closed by the X button

following on from #41561 (closed) @ma1

TB

• flip letterboxing off
• note: extensions.torbutton.maximize_warnings_remaining = 3
• go full screen
• warning does not show (I am not on an HTTPS origin)
• F11 to restore - now the warning shows
• if maximizing instead of FS, it works fine
• ToDo?: suppress the warning in exiting FS or make the warning show in FS
• ToDo?: OK vs X is confusing - X reduces the count, OK doesn't - this seems backwards (but I can see both sides) - anyway, it seems to confuse users. OK means the user (likely read the message and) acknowledged the warning, X means they ignored it and decided to not take action, so IMO this is backwards.

MB

• the same issues above would apply since it is based on TB
• but we also have https://github.com/mullvad/mullvad-browser/issues/44
• here the warning pref doesn't exist and the message cannot be dismissed via X only via Restore button
• also why is MB using Restore and TB using OK as strings?

Flip your LBing pref back on, people!

Honestly, why have the X button at all? Seems convoluted :)