feat: Voice channel creation Flow (#11775)

This PR introduces a new channel type for voice conversations.

ref: #11481 

## Changes

- Add database migration for channel_voice table with phone_number and
provider_config
- Create Channel::Voice model with E.164 phone number validation and
Twilio config validation
- Add voice channel association to Account model
- Extend inbox helpers and types to support voice channels
- Add voice channel setup UI with Twilio configuration form
- Include voice channel in channel factory and list components
- Add API routes and store actions for voice channel creation
- Add comprehensive translations for voice channel management

---------

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

enterprise/app/controllers/enterprise/api/v1/accounts/inboxes_controller.rb

@@ -6,4 +6,28 @@ module Enterprise::Api::V1::Accounts::InboxesController
   def ee_inbox_attributes
     [auto_assignment_config: [:max_assignment_limit]]
   end
+
+  private
+
+  def allowed_channel_types
+    super + ['voice']
+  end
+
+  def channel_type_from_params
+    case permitted_params[:channel][:type]
+    when 'voice'
+      Channel::Voice
+    else
+      super
+    end
+  end
+
+  def account_channels_method
+    case permitted_params[:channel][:type]
+    when 'voice'
+      Current.account.voice_channels
+    else
+      super
+    end
+  end
 end