fix: prevent repetition of template IDs in template_usage_by_day

[mtojek]

Fixes: #8690

Here is the dump from template_ids:

coder-# SELECT * FROM template_ids;
         from_          |                                     ids                                     
------------------------+-----------------------------------------------------------------------------
 2023-07-19 00:00:00+00 | {0d286645-29aa-4eaf-9b52-cc5d2740c90b}
 2023-07-20 00:00:00+00 | {071f39f5-d956-44b0-8849-7715059e2b2e,0d286645-29aa-4eaf-9b52-cc5d2740c90b}
 2023-07-20 00:00:00+00 | {0d286645-29aa-4eaf-9b52-cc5d2740c90b}
 2023-07-21 00:00:00+00 | {071f39f5-d956-44b0-8849-7715059e2b2e,0d286645-29aa-4eaf-9b52-cc5d2740c90b}
 2023-07-21 00:00:00+00 | {0d286645-29aa-4eaf-9b52-cc5d2740c90b}
 2023-07-22 00:00:00+00 | {0d286645-29aa-4eaf-9b52-cc5d2740c90b}
(6 rows)

We need to have distinct records for every day in from_, otherwise this part of the query fails with more than one row returned by a subquery used as an expression.

[johnstcn]

This is a difficult thing to test due our current daily aggregation setup. Approving to unblock.