test: add tests against published client (#2752)

# What does this PR do?
closes #2751

## Test Plan

---------

Co-authored-by: Nathan Weinberg <31703736+nathan-weinberg@users.noreply.github.com>

.github/actions/setup-runner/action.yml

@@ -5,6 +5,10 @@ inputs:
     description: The Python version to use
     required: false
     default: "3.12"
+  client-version:
+    description: The llama-stack-client-python version to test against (latest or published)
+    required: false
+    default: "latest"
 runs:
   using: "composite"
   steps:
@@ -20,8 +24,17 @@ runs:
       run: |
         uv sync --all-groups
         uv pip install ollama faiss-cpu
-        # always test against the latest version of the client
-        # TODO: this is not necessarily a good idea. we need to test against both published and latest
-        # to find out backwards compatibility issues.
-        uv pip install git+https://github.com/meta-llama/llama-stack-client-python.git@main
+
+        # Install llama-stack-client-python based on the client-version input
+        if [ "${{ inputs.client-version }}" = "latest" ]; then
+          echo "Installing latest llama-stack-client-python from main branch"
+          uv pip install git+https://github.com/meta-llama/llama-stack-client-python.git@main
+        elif [ "${{ inputs.client-version }}" = "published" ]; then
+          echo "Installing published llama-stack-client-python from PyPI"
+          uv pip install llama-stack-client
+        else
+          echo "Invalid client-version: ${{ inputs.client-version }}"
+          exit 1
+        fi
+
         uv pip install -e .