Remove sub from Userinfo response for password grant clients

[nynymike]

There is no point to a pairwise sub claim for clients using the password grant. The client already has a username, which can be correlated. Just return the username as the sub value.

[uprightech]

@nynymike , can we close this too ?

[yuriyz]

Code in user info is a bit outdated, sub value construction is centralized in grant.getSub(). Corrected it in 5d9b11b

Closing ticket.
@uprightech PR instead of direct commit would be better so we can catch such kind of improvements in first place.

[uprightech]

Sorry , my bad , I realized I commited to the main repo instead of a PR.