feat: Add manual WhatsApp templates sync with UI (#12007)

Fixes https://github.com/chatwoot/chatwoot/issues/9600

**Summary**
- Added manual WhatsApp templates sync functionality accessible via UI
- Added refresh button in both inbox settings and template picker modal
- Enhanced template picker to always show for WhatsApp Cloud channels
(even when empty)


**Preview**

<img width="1456" height="798" alt="CleanShot 2025-07-22 at 14 15 28@2x"
src="https://github.com/user-attachments/assets/8a04ff26-61fa-42ee-a1b8-5e06433ae6e0"
/>


<img width="2376" height="1574" alt="CleanShot 2025-07-22 at 14 19
24@2x"
src="https://github.com/user-attachments/assets/1c772034-04ff-484d-88dd-ca8123e93065"
/>

---------

Co-authored-by: iamsivin <iamsivin@gmail.com>

app/policies/inbox_policy.rb

@@ -57,4 +57,8 @@ class InboxPolicy < ApplicationPolicy
   def avatar?
     @account_user.administrator?
   end
+
+  def sync_templates?
+    @account_user.administrator?
+  end
 end