DM-39876: Force v1 pydantic API if running v2

[timj]

Checklist

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

[codecov]

Codecov Report

Patch coverage: 50.00% and project coverage change: -0.09 ⚠️

Comparison is base (07d78ed) 82.78% compared to head (4953f65) 82.69%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #350      +/-   ##
==========================================
- Coverage   82.78%   82.69%   -0.09%     
==========================================
  Files          66       66              
  Lines        7237     7246       +9     
  Branches     1408     1291     -117     
==========================================
+ Hits         5991     5992       +1     
- Misses        999     1006       +7     
- Partials      247      248       +1     

Impacted Files	Coverage Δ
python/lsst/pipe/base/_task_metadata.py	96.63% <50.00%> (-0.93%)	⬇️
python/lsst/pipe/base/graph/quantumNode.py	86.15% <50.00%> (-2.56%)	⬇️
...ython/lsst/pipe/base/tests/mocks/_storage_class.py	51.38% <50.00%> (-0.39%)	⬇️

... and 1 file with indirect coverage changes

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