User is reinidexed for every user group membership when authenticating via LDAP

When a user authenticates with Liferay via LDAPAuth, the user is reindexed once for every user group that they are a member of (whether the user groups are from LDAP or if they were non-LDAP user groups). For example, if a user is a member of 100 user groups, they will be reindexed 100 times, even if there are no actual user group membership changes.

Performance can be improved if the user is only reindexed if user group membership changes, and only reindexed once in total at the end of all user group membership changes.