Allow more relaxed artifact path req enforcement

Only enforce whitelist entries are unused if the enforcement variable
is set to "true" or "strict". If set to something else (e.g. "relaxed"),
allow redundant whitelist entries.

This also enables adding wildcard entries, which were previously
considered unused.

Test: downstream
Bug: 117637311
Bug: 80410283
Change-Id: I67a84f8ecfad5fa68c21ee728f1e3085ef89fbcf