fix: Disable push notifications (#11786)

# Pull Request Template

## Description

Fixes
[CW-4512](https://linear.app/chatwoot/issue/CW-4512/cant-turn-off-push-notification-toggle)
https://github.com/chatwoot/chatwoot/issues/11760

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

app/javascript/dashboard/routes/dashboard/settings/profile/NotificationPreferences.vue

@@ -75,10 +75,34 @@ export default {
     onRegistrationSuccess() {
       this.hasEnabledPushPermissions = true;
     },
-    onRequestPermissions() {
-      requestPushPermissions({
-        onSuccess: this.onRegistrationSuccess,
-      });
+    onRequestPermissions(value) {
+      if (value) {
+        // Enable / re-enable push notifications
+        requestPushPermissions({
+          onSuccess: this.onRegistrationSuccess,
+        });
+      } else {
+        // Disable push notifications
+        this.disablePushPermissions();
+      }
+    },
+    disablePushPermissions() {
+      verifyServiceWorkerExistence(registration =>
+        registration.pushManager
+          .getSubscription()
+          .then(subscription => {
+            if (subscription) {
+              return subscription.unsubscribe();
+            }
+            return null;
+          })
+          .finally(() => {
+            this.hasEnabledPushPermissions = false;
+          })
+          .catch(() => {
+            // error
+          })
+      );
     },
     getPushSubscription() {
       verifyServiceWorkerExistence(registration =>