Modify the showAppBubble method to be showOrHideAppBubble

Depending on the state of the app bubble (if it already exists),
calling this method might do different things:
- If the app bubble already exists & isn't open, open it
- If the app bubble already exists & is open, close it
- If the app bubble doesn't exist, add it & open it

Bug: 253320821
Test: atest BubblesTest
Change-Id: I707af3b46d84c97d8c864cab33dfe7d8e49921c7