perf(aci): Cache Group lookup for process_workflows/trigger_action

[kcons]

For process_workflows_event, querying for Group is one of the primary required queries.
It's frequently very fast (~1ms), but at times we've observed it taking 100ms or more. Perhaps more significantly, querying for Group by ID is the most common query the app does, and we're part of htat.
Given that this task runs after post_process, which does read Group through the cache, the Group we're processing should nearly always be in the cache, so here we expect a very high hit rate, a significant reduction in query volume to the database, and improvement in some of our wost case task latency.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/workflow_engine/tasks/utils.py	0.00%	1 Missing ⚠️

Additional details and impacted files

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- Coverage   81.21%   81.21%   -0.01%     
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  Files        8584     8584              
  Lines      380140   380140              
  Branches    24106    24106              
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- Hits       308734   308733       -1     
- Misses      71060    71061       +1     
  Partials      346      346