Reorder overflow button with kotlin refactor

Add overflow button when overflow is created
Reorder overflow button instead of remove+add
Convert overflow view provider to kotlin

Bug: 161396059
Test: toggle all themes, display size; dismiss single bubble /
entire stack; promote bubble from overflow: no regressions

Change-Id: Iee68c982d1591de4f010aac6c620c7353737bc11
3 files changed