video: Handle Cocoa desktop mode switch inhibition in the video layer

The X backend had the same issue, so both Cocoa and X can be handled in the same location.

src/video/SDL_video.c

@@ -1435,7 +1435,7 @@ void SDL_SetDesktopDisplayMode(SDL_VideoDisplay *display, const SDL_DisplayMode
 {
     SDL_DisplayMode last_mode;
 
-    if (display->fullscreen_window) {
+    if (display->fullscreen_window || display->device->setting_display_mode) {
         // This is a temporary mode change, don't save the desktop mode
         return;
     }

src/video/cocoa/SDL_cocoamodes.m

@@ -433,7 +433,7 @@ static void Cocoa_DisplayReconfigurationCallback(CGDirectDisplayID displayid, CG
         }
     }
 
-    if ((flags & kCGDisplaySetModeFlag) && !_this->setting_display_mode) {
+    if (flags & kCGDisplaySetModeFlag) {
         if (display) {
             CGDisplayModeRef moderef = CGDisplayCopyDisplayMode(displayid);
             if (moderef) {