fix: docker failing to start container[pydantic] (#3460)

# What does this PR do?
Pinning to latest pydantic version 2.11.9 as sometime we are picking
older version and failing to start container in github actions :
1775026312
Closes https://github.com/llamastack/llama-stack/issues/3461

## Test Plan
Tested locally with the following commands to start a container

Build container
`llama stack build --distro starter --image-type container`
start container `docker run -d -p 8321:8321 --name llama-stack-test
distribution-starter:0.2.21`
check health http://localhost:8321/v1/health

Couldnt repro with older version(`2.8.2`), but `2.11.9` pydantic is able
to start the container

https://pypi.org/project/pydantic/#history , 2.11.9 is the latest
version

pyproject.toml

@@ -36,7 +36,7 @@ dependencies = [
     "prompt-toolkit",
     "python-dotenv",
     "python-jose[cryptography]",
-    "pydantic>=2",
+    "pydantic>=2.11.9",
     "rich",
     "starlette",
     "termcolor",
@@ -141,7 +141,7 @@ docs = [
     "sphinxcontrib.openapi",
     "requests",
 ]
-codegen = ["rich", "pydantic", "jinja2>=3.1.6"]
+codegen = ["rich", "pydantic>=2.11.9", "jinja2>=3.1.6"]
 benchmark = [
     "locust>=2.39.1",
 ]