DM-45791: Use new butler import API in tests

[timj]

Requires lsst/daf_butler#1061

Checklist

• added documentation for a new migration script

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 58.20%. Comparing base (62059b9) to head (609976b).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #44      +/-   ##
==========================================
- Coverage   58.41%   58.20%   -0.21%     
==========================================
  Files          38       38              
  Lines        1414     1407       -7     
  Branches      298      297       -1     
==========================================
- Hits          826      819       -7     
  Misses        548      548              
  Partials       40       40              

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[andy-slac]

Looks great, thanks for adding do-not-merge GA!