AlsoKnownAs schema should always require accounts to be an array even if it is empty

[Geo25rey]

This DID (did:3:kjzl6cwe1jw147ko5yhnbxk53v2sc8wjrlgirai2tfujdwyw7vjvsej1zbs60gw) has accounts in the AlsoKnownAs schema as undefined, but in the IDX type definition it should always be an array. The schema and the type definition should match. At this point, it would probably make more sense to change the type definition rather than the schema so migration doesn't need to happen.