Revert "Bump HF version" (#9600)

Reverts pytorch/executorch#9408

Author: larryliu0820

.github/workflows/trunk.yml

@@ -536,8 +536,9 @@ jobs:
         git clone https://github.com/huggingface/optimum-executorch
         cd optimum-executorch
         # There is no release yet, for CI stability, always test from the same commit on main
-        git checkout 1907349524b5f2d61f9c04d2e985da826d4308ba
-        pip install .[tests]
+        git checkout 6a7e83f3eee2976fa809335bfb78a45b1ea1cb25
+        pip install .
+        pip install accelerate sentencepiece
         pip list
         echo "::endgroup::"
 

requirements-examples.txt

@@ -2,4 +2,4 @@
 # TODO: Make each example publish its own requirements.txt
 timm == 1.0.7
 torchsr == 1.0.4
-transformers ==4.50.1
+transformers ==4.47.1