fix(federation): Allow Oracles empty strings #15115

Job	Run time
changes	8s
integration-sqlite (capabilities_features, 8.1, main)	1m 39s
integration-sqlite (collaboration_features, 8.1, main)	2m 21s
integration-sqlite (comments_features, 8.1, main)	1m 56s
integration-sqlite (dav_features, 8.1, main)	5m 37s
integration-sqlite (features, 8.1, main)	6m 12s
integration-sqlite (federation_features, 8.1, main)	3m 10s
integration-sqlite (--tags ~@large files_features, 8.1, main)	9m 12s
integration-sqlite (filesdrop_features, 8.1, main)	1m 48s
integration-sqlite (openldap_features, 8.1, main)	1m 12s
integration-sqlite (openldap_numerical_features, 8.1, main)	1m 38s
integration-sqlite (ldap_features, 8.1, main)	1m 43s
integration-sqlite (remoteapi_features, 8.1, main)	59s
integration-sqlite (setup_features, 8.1, main)	1m 5s
integration-sqlite (sharees_features, 8.1, main)	2m 30s
integration-sqlite (sharing_features, 8.1, main)	11m 12s
integration-sqlite (videoverification_features, 8.1, main)	4m 35s
integration-sqlite-summary	4s
	57m 1s

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