Expanded view handle should be the size of the dots

Handle was using the width of the expanded view. Which meant the entire
width was clickable and draggable.
Reduce the size of the handle to the dots and some padding aronud it.

Bug: 283991264
Test: manual, tap on area close to the edge of bubble expanded view
Change-Id: Ib36e024ba1cd9dbd0ed31ce1c294f0ad9cf77359