Cannot reply to a comment reply

Problem/Motivation

The reply button is missing when you want to reply to a comment reply.

Steps to reproduce

1. Create a topic and enable comments
2. Create a comment as user 1
3. As a different user reply to this comment
4. As user 1 try to reply to the reply created above

Proposed resolution

Fix the if check in social_mentions module.

Remaining tasks

User interface changes

API changes

Data model changes