feat(ci): add support for running vision inference tests (#2972)

This PR significantly refactors the Integration Tests workflow. The main
goal behind the PR was to enable recording of vision tests which were
never run as part of our CI ever before. During debugging, I ended up
making several other changes refactoring and hopefully increasing the
robustness of the workflow.

After doing the experiments, I have updated the trigger event to be
`pull_request_target` so this workflow can get write permissions by
default but it will run with source code from the base (main) branch in
the source repository only. If you do change the workflow, you'd need to
experiment using the `workflow_dispatch` triggers. This should not be
news to anyone using Github Actions (except me!)

It is likely to be a little rocky though while I learn more about GitHub
Actions, etc. Please be patient :)

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

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

@@ -0,0 +1,48 @@
+name: 'Setup Test Environment'
+description: 'Common setup steps for integration tests including dependencies, providers, and build'
+
+inputs:
+  python-version:
+    description: 'Python version to use'
+    required: true
+  client-version:
+    description: 'Client version (latest or published)'
+    required: true
+  provider:
+    description: 'Provider to setup (ollama or vllm)'
+    required: true
+    default: 'ollama'
+  run-vision-tests:
+    description: 'Whether to setup provider for vision tests'
+    required: false
+    default: 'false'
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Install dependencies
+      uses: ./.github/actions/setup-runner
+      with:
+        python-version: ${{ inputs.python-version }}
+        client-version: ${{ inputs.client-version }}
+
+    - name: Setup ollama
+      if: ${{ inputs.provider == 'ollama' }}
+      uses: ./.github/actions/setup-ollama
+      with:
+        run-vision-tests: ${{ inputs.run-vision-tests }}
+
+    - name: Setup vllm
+      if: ${{ inputs.provider == 'vllm' }}
+      uses: ./.github/actions/setup-vllm
+
+    - name: Build Llama Stack
+      shell: bash
+      run: |
+        uv run llama stack build --template ci-tests --image-type venv
+
+    - name: Configure git for commits
+      shell: bash
+      run: |
+        git config --local user.email "github-actions[bot]@users.noreply.github.com"
+        git config --local user.name "github-actions[bot]"