Fixed the animations of Messaging Layout, leading to overlaps

The animations could go wild at times, leading to overlapping
messages and ugly renderings. This improves the animations
overall and fixes those cases.

Test: add messages, observe animations
Fixes: 78114531
Fixes: 80409521
Change-Id: I6f21b87706ccc2e85f1edbd9489e4bf7e686d7d8