Wall to Wall button crashes Wall portlet

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X EE, Master
• Fix Version/s: 7.0.X EE, 7.1.X, Master
• Component/s: Social Networking
• Labels:
  • NAT
  • ee-ts
• Branch Version/s:
  7.0.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 5
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/49353

Wall to Wall link should redirect to a Wall portlet that contains only messages between the two persons, but right now the portlet will crash after hitting Wall to Wall button.

Reproduce: 
1. Create another 2 users in addition to test. Make sure these new users' screen names do not have dot character, see PS for reason.
2. In personal profile page of test and two new users, add "Summary", "Requests" and "Wall" portlets.
3. Make all three users friend to each other
4. Log in as test and write on the other two users' wall (by going to their profile page), and do vice versa.
5. Log in as any one of the users, for example, test and go to profile page. You will be able to see the other two guys messages on your own wall.
6. Click one of the Wall to Wall buttons

Expected: It should redirect to a wall portlet that contains only messages between the two persons, without messages from the third one.
Actual: Wall portlet crashes.

PS: For cases when the wall user has screen name with dot character, there will be another bug occuring before this issue can be reproduced. 

That bug is addressed in LPS-72836, but since this current issue is more critical and both issues are not related in terms of code logic, so I am fixing this one first.