fix: add modeling_mixtral_te.py to opengenome2 recipe and fix imports for sparse checkout

CI uses sparse-checkout, so each recipe job only has its own directory.
The opengenome2_mixtral_native_te tests were importing modeling_mixtral_te
from the shared mixtral_native_te recipe path, which does not exist in
the sparse checkout.

Fix:
- Copy modeling_mixtral_te.py to opengenome2_mixtral_native_te recipe root
- Register the copy in check_copied_files.py source-destination map
- Update test imports to use local recipe root instead of shared path

Signed-off-by: svc-bionemo <267129667+svc-bionemo@users.noreply.github.com>

Author: svc-bionemo