UBERF-6802: Improve create chat message performance

[kristina-fefelova]

Got rid of a lot of unnecessary findAll
Previously there were > 1000 findAll requests for 15 messages in a chat of 8 members, now 45 (3 per message and no longer depends on the number of members)

Before:

After:

_{Huly®: UBERF-6826}