Remove references to undefined properties (e.g. extended audit log shows $$not found: groupAuditLogFilterColumnServerUsername$$)

When viewing extended audit results, the columns are:

• Date
• Actor
• Engine
• Summary
• Duration
• Query count
• $$not found: groupAuditLogFilterColumnServerUsername$$
• Server
• IP address
• Entry ID

Looks to be related to GRP-2504, where `groupAuditLogFilterColumnServerUsername` was renamed as groupAuditLogFilterColumnUser for use in subject delete audits. Both values probably need to be defined.