feat: Update API for contact avatar (#4719)

Added the ability to update the contact's avatar via API and Dashboard.

- Contact create and update APIs can now accept avatar attachment parameters [form data].
- Contact create and update endpoints can now accept the avatar_url parameter.[json]
- API endpoint to remove a contact avatar.
- Updated Contact create/edit UI components with avatar support

Fixes: #3428

app/policies/contact_policy.rb

@@ -39,6 +39,10 @@ class ContactPolicy < ApplicationPolicy
     true
   end
 
+  def avatar?
+    true
+  end
+
   def destroy?
     @account_user.administrator?
   end