Always surface ui_error alerts, including in fullscreen

ui_error_specific swallowed every error when settings_current.full_screen
was set, returning 0 without ever calling aqua_verror. That made
runtime errors during fullscreen play invisible: RZX desync, disk
read failures on a mounted image, tape malformed-block during
playback of a tape mounted before fullscreen, Spectranet socket
failures, sound device hot-unplug — all silently dropped.

macOS native fullscreen overlays alerts on the fullscreen Space the
way it handles any other fullscreen app, so the original concern
(panel hidden under the borderless overlay) no longer applies.
Distraction-free is the OS's job via the menu-bar auto-hide; a
malfunction is not the happy path.

Author: morozov

ui/cocoa/cocoaerror.m

@@ -37,7 +37,6 @@
 
 #include "fuse.h"
 #include "ui/ui.h"
-#include "settings.h"
 
 static int
 aqua_verror( ui_error_level severity, const char *message )
@@ -66,8 +65,5 @@
 int
 ui_error_specific( ui_error_level severity, const char *message )
 {
-  if ( !settings_current.full_screen ) {
-    return aqua_verror( severity, message );
-  }
-  return 0;
+  return aqua_verror( severity, message );
 }