Add bug component ID to HWUI's OWNERS

This was raised for another area recently to ease routing,
seems harmless and potentially helpful for bots.

go/xts-owners-policy is XTS-specific, but same syntax applies.

Bug: N/A
Test: N/A
Change-Id: I1a4fa3f75e0d4f4f1d61f2028a14de65d03e744c