= Searching by user attribute no longer case insensitive

When searching for users by user attribute, Keycloak no longer searches for user attribute names forcing lower case comparisons. The goal of this change was to speed up searches by using Keycloak's native index on the user attribute table. If your database collation is case-insensitive, your search results will stay the same. If your database collation is case-sensitive, you might see less search results than before.
