Final Kotlin conversion of PackageIconLoader

Built successfully against Kotlin 1.7 and with -Werror turned on. Added androidx.core_core to Android.bp to allow replacement of deprecated function calls with supported versions in androidx.

Bug: 239665416

Test: manual testing with bramble device, unit tests ran with atest QuickSearchBoxTests with result:
Summary (Test executed with 1 devices.)
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arm64-v8a QuickSearchBoxTests: Passed: 50, Failed: 0, Ignored: 0, Assumption Failed: 0,

All tests passed!

Change-Id: I784aa671a081a58794e62b29bc95cf11a8341e7a
2 files changed