POC: asExpired flag related fixes

asExpired is blocked by NFC, it should circumvent NFC.

Also, it should be "forwarded", to ensure "really latest" is received by client (in case of proxying another Nexus).

Issues
https://issues.sonatype.org/browse/NEXUS-6177
https://issues.sonatype.org/browse/NEXUS-6178

CI
TBD