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/helper/specs/editorContentHelper.spec.js

@@ -48,6 +48,7 @@ describe('getContentNode', () => {
         {
           userId: content.id,
           userFullName: content.name,
+          mentionType: 'user',
         }
       );
     });