DM-54108: Add private function for synchronizing collection chain structure

[dhirving]

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes
• (if changing dimensions.yaml) make a copy of dimensions.yaml in configs/old_dimensions

[codecov]

Codecov Report

❌ Patch coverage is 11.42857% with 31 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.47%. Comparing base (a30e528) to head (3af0836).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
.../butler/_rubin/synchronize_collection_structure.py	0.00%	27 Missing ⚠️
...thon/lsst/daf/butler/registry/collections/_base.py	50.00%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1335      +/-   ##
==========================================
- Coverage   89.52%   89.47%   -0.06%     
==========================================
  Files         369      370       +1     
  Lines       50175    50204      +29     
  Branches     5874     5882       +8     
==========================================
  Hits        44918    44918              
- Misses       3869     3897      +28     
- Partials     1388     1389       +1     

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