Implement subtype advertising by advertising an additional PTR record if subtype advertising was requested. For an advertiser a subtype is just an additional PTR record, so this just involves plumbing the subtype down to MdnsRecordRepository, which includes the additional record in the service registration. Bug: 266167702 Test: atest (cherry picked from https://android-review.googlesource.com/q/commit:ce44beb7aa3d17dabab5e596a1b27cb9422e076e) Merged-In: I09e780af25149162f16bd75410ddc50f160a0dab Change-Id: I09e780af25149162f16bd75410ddc50f160a0dab