Auth: Force lowercase login/email for users (#86359)
* [WIP]: Force lowercase login/email for user CRUD
* warn and remove use of userCaseInsensitiveLogin check
* remove log warning
* reimplementation of the caseinsensitive
* need to decide if we want the conflict check or not
* remvoved the tests for conflict user by getEmail, getLogin
* added tests for user lowercase migration
* wip: emails next
* tests for email lowercasing
* review comments
* optimized login and email lookup before migrating
(cherry picked from commit e394e16073)