fix: Playground Container Issue (#1868)

**What does this PR do?**

This PR fixes a build issue with the Containerfile caused by missing
requirement `llama-stack`. It updates the Containerfile to include the
necessary requirements and upgrades the Python version to ensure
successful builds.

**Test Plan**
The updated Containerfile has been tested, and the build now completes
successfully with the required dependencies included.

llama_stack/distribution/ui/Containerfile

@@ -1,7 +1,7 @@
 # More info on playground configuration can be found here:
 # https://llama-stack.readthedocs.io/en/latest/playground
 
-FROM python:3.9-slim
+FROM python:3.12-slim
 WORKDIR /app
 COPY . /app/
 RUN /usr/local/bin/python -m pip install --upgrade pip && \

llama_stack/distribution/ui/requirements.txt

@@ -2,3 +2,4 @@ streamlit
 pandas
 llama-stack-client>=0.0.55
 streamlit-option-menu
+llama-stack>=0.1.9