fix(aci): Ensure QuerySubscription changes to AlertRule are reflected on Detector DataSource

[kcons]

Fixes ACI-505.

[codecov]

Codecov Report

❌ Patch coverage is 70.00000% with 6 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ry/workflow_engine/migration_helpers/alert_rule.py	70.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #102334    +/-   ##
=========================================
  Coverage   80.95%    80.96%            
=========================================
  Files        8769      8770     +1     
  Lines      389622    389754   +132     
  Branches    24777     24777            
=========================================
+ Hits       315431    315561   +130     
- Misses      73813     73815     +2     
  Partials      378       378            

[kcons]

FYI, all the uncovered lines are for the "if for some weird reason the snuba/subscription/datasource id doesn't actually exist, log and exit" cases. I find that adding test cases for every control flow branch even the ones that just log a thing isn't super useful, but just assuming things exist and allowing the exception when they don't to be caught and reported up the stack (as is the design here) tends to make cursor bot and seer bot freak out.

[saponifi3d]

lgtm to fix the legacy api, but not sure if this is a problem in the new api as well -- we should probably double check that as well.

[saponifi3d]

since this code is meant to be temporary (the directory is meant to be deletable once we want to start removing the dual write code). should we have this live somewhere else? it seems like this only affects metric alerts, so maybe somewhere in the incidents app?

[kcons]

I think we want this to be deleted to, pending confirmation that we are actually updating QuerySubscriptions properly on AlertRule-less DataSources.