fix(core): Notification.requestPermission() deadlock regression

Author: lucasfernog

.changes/notification-regression.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Fixes `Notification.requestPermission()` deadlock.

core/tauri/src/endpoints.rs

@@ -126,7 +126,7 @@ impl Module {
           })
         }
       }
-      Self::Notification(cmd) => resolver.respond_closure(move || {
+      Self::Notification(cmd) => resolver.respond_async(async move {
         cmd
           .run(window, config, &package_info)
           .and_then(|r| r.json)