Fix ClassCastException in 2nd phase resolution.

This has been broken since the original Oreo implementation was added
https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r1/core/java/android/app/InstantAppResolverService.java#118

Bug: 118635643
Test: Manual build and run locally.
Change-Id: Ie3f2ca2d0baf4ebcedbf75753cc2cdbcfa4b3e1b