NOTE: Re-submitting this (was previously reviewed in D8708) for backporting to 2.90.
When Blender is started in fullscreen mode from the command line,
or if the fullscreen state is saved in the startup file, all temporary windows
will also open in fullscreen mode. When closing the fullscreen File Browser,
Blender would either crash or parent window becomes black.
This does not happen if the Blender switches to full screen manually.
NSWindowCollectionBehaviorFullScreenPrimary should be set for windows that
can enter full-screen mode. Otherwise macOS will turn the wrong window into
full-screen.
Similar fix: rB4b39de677d20