Reset the static preloaded icon result once launcher is hidden

- In the case where the system does not play the requested animation
  we can still ensure that this doesn't result in a leak of the
  activity by resetting the result when launcher is hidden (which
  happens after the launch transition)

Bug: 285995223
Test: Presubmit
Test: Take heapdump after repro steps in b/285995223#comment6 and verify
      there are no lingering static icon load results

Change-Id: I1d169df158cfaab64fbe1f4ce597d8f73d86a1c1