chore: add Twilio voice support to TwilioSms channel

app/javascript/shared/mixins/inboxMixin.js

@@ -1,4 +1,4 @@
-import { INBOX_TYPES } from 'dashboard/helper/inbox';
+import { INBOX_TYPES, isVoiceCallEnabled } from 'dashboard/helper/inbox';
 
 export const INBOX_FEATURES = {
   REPLY_TO: 'replyTo',
@@ -59,8 +59,8 @@ export default {
     isALineChannel() {
       return this.channelType === INBOX_TYPES.LINE;
     },
-    isAVoiceChannel() {
-      return this.channelType === INBOX_TYPES.VOICE;
+    voiceCallEnabled() {
+      return isVoiceCallEnabled(this.inbox);
     },
     isAnEmailChannel() {
       return this.channelType === INBOX_TYPES.EMAIL;