fix: task that repairs bad docevents related to subseries removals

[rjsparks]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 25.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 88.71%. Comparing base (18cea10) to head (097618b).
Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
ietf/sync/tasks.py	25.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9053      +/-   ##
==========================================
- Coverage   88.71%   88.71%   -0.01%     
==========================================
  Files         320      321       +1     
  Lines       41793    41834      +41     
==========================================
+ Hits        37078    37111      +33     
- Misses       4715     4723       +8     

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