Restore macos window proxy icon

[LukeHHA]

Fixes #12189
Added macOS Proxy icon back. Restoring the previous behaviour shown in issue #12189. This does reintroduce the * problem in the title bar. #11542 removed the proxy icon for this reason as far as I can tell. Removing the [*] from the QString here:

windowTitle = QString("%1 - %2").arg(customWindowTitlePart, BaseWindowTitle);

oddly seemed to fix the problem and, by visual testing, the titles all appeared correct but this does not seem like the proper fix. I could not figure out why it was happening. However, as per the discussion under issue #12189 , proxy icons were never intended to be removed. I understand this may not be an acceptable compromise however. I also used the StackedWidgetIndex enum to check against SettingsScreen instead of the old magic number used before this feature was removed. As well as checking against the PasswordGeneratorScreen as it also did not make sense to have the proxy icon at this location.

Screenshots

Screenshot would not register the actual application for some reason.

Testing strategy

Visually testing the application. This did confirm that the * only appears right after creating a database and disappears as soon as you click to another screen.

• Confirmed proxy icon appears under saved vault
• Confirmed that it disappears in settings and password generator
• Confirmed it returns after switching back
  I could not find a way to actually test in code that the proxy icon was being rendered

Type of change

• ✅ Bug fix (non-breaking change that fixes an issue)