modifyRegistrationMetadata api and UpdateDvObjectPIDMetadataCommand will create filePIDs even if they are not in use

[qqmyers]

The UpdateDvObjectPIDMetadataCommand, used by the /datasets/{id}/modifyRegistrationMetadata and /dataset/{id}/modifyRegistrationPIDMetadataAll api calls (and my implementation for #4760) doesn't check the file PID setting, so it will create one when it shouldn't (ignoring changes for #5505 which could flag/fail if the file doesn't currently have a PID). Further, if it should (the filePID flag allows), there would still be an issue if the files have no PID and PIDs are now allowed and the protocol/authority/filePID naming scheme (e.g. dependent) would cause an issue. Creating a PR that adds this check, mirroring the code in FinalizeDatasetPublicationCommand.