DM-34884: Disable checks of schema checksums

[andy-slac]

The code that calculates checksums is still there, will be removed when
we are sure that we never need it.

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes

[codecov]

Codecov Report

Merging #686 (1ecbe8d) into main (cdca06c) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #686      +/-   ##
==========================================
- Coverage   84.28%   84.27%   -0.02%     
==========================================
  Files         243      243              
  Lines       31098    31096       -2     
  Branches     5245     5245              
==========================================
- Hits        26212    26207       -5     
- Misses       3718     3724       +6     
+ Partials     1168     1165       -3     

Impacted Files	Coverage Δ
python/lsst/daf/butler/registry/managers.py	94.93% <100.00%> (+2.16%)	⬆️
python/lsst/daf/butler/registry/versions.py	65.00% <100.00%> (-3.65%)	⬇️

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[timj]

This matches what we agreed in the meeting today.