Only invoke LaunchOrConvert transition on bubble bar

- Until we refactor the transitions to account for floating bubbles
  layout (b/408453889) we should also only enable the new flow
  on large screens where bubblebar is enabled

Fixes: 408955678
Flag: EXEMPT bugfix
Test: Launch an app into a bubble on a phone
Change-Id: I5fb898a07cbbd5a8876e0c2cb4876894ad5a8a2a