add back transformer engine install

[pstjohn]

Adds back the custom transformer engine install to avoid the import error on python debugging. https://nvidia.slack.com/archives/C074Z808N05/p1737753519355939

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.75%. Comparing base (60a6dad) to head (abfb04a).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #658   +/-   ##
=======================================
  Coverage   86.75%   86.75%           
=======================================
  Files         118      118           
  Lines        7059     7059           
=======================================
  Hits         6124     6124           
  Misses        935      935           

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