feat(notifications): adds backfill for weekly report settings

[scefali]

Need to backfill the weekly report settings because it comes from a different source than the rest of the notifications

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/0574_backfill_weekly_report_settings.py ()

--
-- MIGRATION NOW PERFORMS OPERATION THAT CANNOT BE WRITTEN AS SQL:
-- Raw Python operation
--

[codecov]

Codecov Report

Merging #58168 (fa264ee) into master (2f5451f) will increase coverage by 0.48%.
Report is 16 commits behind head on master.
The diff coverage is n/a.

❗ Current head fa264ee differs from pull request most recent head 05f8f95. Consider uploading reports for the commit 05f8f95 to get more accurate results

@@            Coverage Diff             @@
##           master   #58168      +/-   ##
==========================================
+ Coverage   78.57%   79.05%   +0.48%     
==========================================
  Files        5135     5135              
  Lines      223490   223455      -35     
  Branches    37626    37617       -9     
==========================================
+ Hits       175597   176660    +1063     
+ Misses      42200    41145    -1055     
+ Partials     5693     5650      -43     

see 123 files with indirect coverage changes