Bound the thumbnail insets to the launcher insets

- We currently end up using the launcher insets when swiping
  up into overview due to how we scale the target rect to
  the source bounds, but the thumbnail crop is calculated
  only from the task thumbnail insets.  For apps that are
  letterboxed, this results in a jump after the transition
  completes when we crop too far (including the letterbox)
  and end up showing the task background.

  For now, since we are just cropping by the launcher
  insets, we can also take the min of those and the
  thumbnail insets to calculate the thumbnail view crop.

Bug: 151770104
Test: Test swiping up with a normal app, a letterboxed app
      (like authenticator), an app that has no insets (like
Change-Id: I08342b19c54f9078be4613fca9024e2558403bc9