feat: Add the ability to mention team in private message (#11758)

This PR allows agents to mention entire teams in private messages using
`@team_name` syntax. When a team is mentioned, all team members with
inbox access are automatically notified. The scheme changes can be found
[here](https://github.com/chatwoot/prosemirror-schema/pull/34).

---------

Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/javascript/dashboard/i18n/locale/en/conversation.json

@@ -96,6 +96,10 @@
         "NEXT_WEEK": "Next week"
       }
     },
+    "MENTION": {
+      "AGENTS": "Agents",
+      "TEAMS": "Teams"
+    },
     "CUSTOM_SNOOZE": {
       "TITLE": "Snooze until",
       "APPLY": "Snooze",