Check shortcut icon validity

Check if a shortcut icon is available for the curent user.
This is important for callter provided targets (see
Intent#EXTRA_CHOOSER_TARGETS) which icons are specified by the calling
app.

Bug: 277207798
Test: manual testing with some debug code injections and a custom test
app.

Change-Id: Idcf7f415abb77b585fddbc26e887909b07c8af17
3 files changed