feat(ci): use @next branch from llama-stack-client (#3576)

When we update Stainless (editor changes), the `next` branch gets
updated. Eventually when one decides on a release, you land changes into
`main`. This is the Stainless workflow.

This PR makes sure we follow that workflow by pulling from the `next`
branch for our integration tests.

Author: ashwinb

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

@@ -29,8 +29,8 @@ runs:
 
         # Install llama-stack-client-python based on the client-version input
         if [ "${{ inputs.client-version }}" = "latest" ]; then
-          echo "Installing latest llama-stack-client-python from main branch"
-          uv pip install git+https://github.com/llamastack/llama-stack-client-python.git@main
+          echo "Installing latest llama-stack-client-python from next branch"
+          uv pip install git+https://github.com/llamastack/llama-stack-client-python.git@next
         elif [ "${{ inputs.client-version }}" = "published" ]; then
           echo "Installing published llama-stack-client-python from PyPI"
           uv pip install llama-stack-client

.github/actions/setup-test-environment/action.yml

@@ -44,8 +44,8 @@ runs:
       run: |
         # Install llama-stack-client-python based on the client-version input
         if [ "${{ inputs.client-version }}" = "latest" ]; then
-          echo "Installing latest llama-stack-client-python from main branch"
-          export LLAMA_STACK_CLIENT_DIR=git+https://github.com/llamastack/llama-stack-client-python.git@main
+          echo "Installing latest llama-stack-client-python from next branch"
+          export LLAMA_STACK_CLIENT_DIR=git+https://github.com/llamastack/llama-stack-client-python.git@next
         elif [ "${{ inputs.client-version }}" = "published" ]; then
           echo "Installing published llama-stack-client-python from PyPI"
           unset LLAMA_STACK_CLIENT_DIR