UP-4223 Transactionalize registerUserProfileSelection()

This is a tweak to #450 to apply a transaction aspect on a `ProfileSelectionRegistry` method that wraps multiple profile selection DAO methods, so that those methods are wrapped into a single transaction.

There's some ghost :ghost: in the machine when testing against an Oracle (rather than hsql) RBDMS such that profile selection updates intermittently fail with a unique constraint violation.  :grimacing:  Hoping that it turns out to be this transactionality bug and that applying this aspect makes that ghost go away.