Improve Error Message when LDAP Write Fails due to Lack of User Privileges

Context

This ticket is created based on JRA-42515, after investigations have been conducted to verify the described behavior. Findings of the investigations:

1. Writing user/group data from JIRA to LDAP is supposed to work properly provided:
   1. The LDAP permission type configured in JIRA is Read/Write
   2. The username used for LDAP configuration has Read/Write privileges to LDAP
2. If 1.1 is correct, but 1.2 fails i.e. username without Read/Write privileges, then an unclear/misleading error message might be thrown, making it hard for JIRA admin to troubleshoot the root cause:

   com.atlassian.crowd.exception.runtime.GroupNotFoundException: Group <Unable to create group jira-users in directory 10000 in order to add membership of user user@domain.com (group jira-users found in directory 10000)> does not exist
   

3. This misleading message sounds like the Read/Write permission type of the LDAP directory does not work: unable to add an internal group to the LDAP server in order to add an LDAP user to it.
4. The root cause: the username used for LDAP configuration does not have Read/Write privileges to LDAP

Steps to reproduce & Facts

1. connect JIRA to an LDAP server using Connector type with Read/Write permission type
2. specify a username without Read/Write privileges
3. from User Management -> Users, try adding an LDAP user to an Internal group:
   
   1. When adding an LDAP user to an LDAP group, there's no error message, just a quick refresh in the browser, and the user is NOT added to the group.
4. from User Management -> Groups, try adding an LDAP user to an Internal group:
   
5. from User Management -> Groups, try adding an LDAP user to an LDAP group:
   
   The error message thrown at this step is correct

Suggestion