perf(similarity): in backfill lower time bounds

[JoshFerge]

lower time bounds to 1 minute, as we'll scan less data, and i think this should be plenty of range for it to find the last event sent.

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: src/sentry/tasks/embeddings_grouping/utils.py

Function	Unhandled Issue
get_data_from_snuba	RateLimitExceeded: Query on could not be run due to allocation policies, details: {'CrossOrgQueryAllocationPolicy': ... ... Event Count: 1

---

_{Did you find this useful? React with a 👍 or 👎}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.01%. Comparing base (1a142ab) to head (b36db18).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #73345      +/-   ##
==========================================
- Coverage   78.01%   78.01%   -0.01%     
==========================================
  Files        6632     6632              
  Lines      296126   296126              
  Branches    50999    50999              
==========================================
- Hits       231030   231024       -6     
- Misses      58813    58815       +2     
- Partials     6283     6287       +4     

Files	Coverage Δ
src/sentry/tasks/embeddings_grouping/utils.py	91.07% <ø> (ø)

... and 3 files with indirect coverage changes

[iadityagupta19]

lower time bounds to 1 minute, as we'll scan less data, and i think this should be plenty of range for it to find the last event sent.