Add Distinct User Count Metric

[jesshitchcock]

Details

A prospect reported that totals are not displaying in the F3 section of the SQL Fanouts protection demo dashboard. This was initially suspected to be related to SQL joins fanout protection, but identified it is actually because totals do not display for custom metrics or table calculations.

Proposed Solution

• Add total_users as a metric in the semantic layer (users.yml), this should result in the total being displayed.
• Deploy this change to the demo onrender and check that the total is displayed there

Slack conversation