Add some protologs around switching between bubble UI modes

Also add a dump method on BubblePositioner to include info
from its state that is most relevant for debugging.

Removes unused rotation value.

Flag: EXEMPT - adding protologs
Test: treehugger
Bug: 427284677
Bug: 427611342
Change-Id: I97765f88f596e3a41484feafb57683a7e391189e