MessagingStyle: Fix buggy measure in MessagingLinearLayout

Fixes a bug in MessagingLinearLayout where we would not
recompute the height of it after applying the computed
insets to the text views, leading to incorrect padding
and in rare cases a cut off message at the bottom.

Change-Id: If87a527555158e94e501832e9f49e380cc7da2bb
Test: runtest -x core/tests/coretests/src/com/android/internal/widget/MessagingLinearLayoutTest.java
Fixes: 31463075
(cherry picked from commit 4ac8f40d)