Trial revert of --use-pt-pinned-commit for llava

Now that we've bumped the nightly version, let's make sure that --use-pt-pinned-commit is definitely causing the long running times here.

ghstack-source-id: 252f25c
ghstack-comment-id: 2634989174
Pull Request resolved: #8193

Author: swolchok

.github/workflows/pull.yml

@@ -221,7 +221,7 @@ jobs:
         PYTHON_EXECUTABLE=python bash .ci/scripts/setup-linux.sh "cmake"
 
         # install pybind
-        bash install_executorch.sh --pybind xnnpack --use-pt-pinned-commit
+        bash install_executorch.sh --pybind xnnpack
 
         # install Llava requirements
         bash examples/models/llama/install_requirements.sh