macOS: Disable automatic window tabbing in fullscreen mode (#26600)

Fixes #26534 (this time for real)

Release Notes:

- Fixed issue where Zed would behave weirdly when opening new fullscreen
windows by disabling window tabbing

Apple docs:
https://developer.apple.com/documentation/appkit/nswindow/allowsautomaticwindowtabbing

crates/gpui/src/platform/mac/window.rs

@@ -92,6 +92,8 @@ extern "C" {
 
 #[ctor]
 unsafe fn build_classes() {
+    let _: () = msg_send![class!(NSWindow), setAllowsAutomaticWindowTabbing: NO];
+
     WINDOW_CLASS = build_window_class("GPUIWindow", class!(NSWindow));
     PANEL_CLASS = build_window_class("GPUIPanel", class!(NSPanel));
     VIEW_CLASS = {