fix: crash when WindowButtonsProxy references cleared NSWindow (#33487)

* resets WindowButtonsProxy on window delete on macOS

* fixes reset

* chore: empty commit

Co-authored-by: Gellert Hegyi <[email protected]>
Co-authored-by: Samuel Attard <[email protected]>

shell/browser/native_window_mac.mm

@@ -328,6 +328,8 @@ NativeWindowMac::NativeWindowMac(const gin_helper::Dictionary& options,
       [](NativeWindowMac* window) {
         if (window->window_)
           window->window_ = nil;
+        if (window->buttons_proxy_)
+          window->buttons_proxy_.reset();
       },
       this));