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>

app/javascript/shared/mixins/inboxMixin.js

@@ -63,6 +63,9 @@ export default {
     isATelegramChannel() {
       return this.channelType === INBOX_TYPES.TELEGRAM;
     },
+    isAVoiceChannel() {
+      return this.channelType === INBOX_TYPES.VOICE;
+    },
     isATwilioSMSChannel() {
       const { medium: medium = '' } = this.inbox;
       return this.isATwilioChannel && medium === 'sms';