feat: Add rich template preview for WhatsApp & Twilio Templates (#13206)

This PR introduces a comprehensive, display-only template preview system
for both WhatsApp and Twilio templates rendering of all supported
template types.

This lays the foundation for rich template previews across:
- Template selection modals
- Campaign creation flows
- Message composer
- Message screen.

<img width="1818" height="2058" alt="template-preview"
src="https://github.com/user-attachments/assets/9833b28c-f824-4568-8f74-6da09ac61f62"
/>

---------

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>

theme/icons.js

@@ -423,5 +423,10 @@ export const icons = {
     width: 16,
     height: 16,
   },
+  'quick-reply': {
+    body: `<path d="M.667 6.654 5.315.667v3.326c7.968 0 8.878 6.46 8.656 10.007l-.005-.027c-.334-1.79-.474-4.658-8.65-4.658v3.327z" fill="none" stroke="currentColor" stroke-width="1.333" stroke-linecap="round" stroke-linejoin="round"/>`,
+    width: 15,
+    height: 15,
+  },
   /** Ends */
 };