fix: build_venv expects an extra argument

[cdoern]

What does this PR do?

currently, build_venv.sh expects a distribution_type as the first argument but the only things ever passed are:

1. image name
2. pip dependencies

so distribution_type is never passed in meaning the script errors when calling something like:

llama stack build --image-type venv --template ollama --image-name test

before output:

llama stack build --image-type venv --template ollama --image-name venv-test
Usage: /Users/charliedoern/projects/Documents/llama-stack/llama_stack/distribution/build_venv.sh <distribution_type> <env_name> <pip_dependencies> [<special_pip_deps>]
Example: /Users/charliedoern/projects/Documents/llama-stack/llama_stack/distribution/build_venv.sh <distribution_type> mybuild ./my-stack-build.yaml 'numpy pandas scipy'
Failed to build target venv-test with return code 1
Run config path is empty

after:

llama stack build --image-type venv --template ollama --image-name venv-test
Environment 'venv-test' already exists, re-using it.
Using virtual environment venv-test
Using CPython 3.13.0 interpreter at: /opt/homebrew/opt/[email protected]/bin/python3.13
Creating virtual environment at: venv-test
Activate with: source venv-test/bin/activate
Using Python 3.13.0 environment at: venv-test
Resolved 55 packages in 640ms
      Built fire==0.7.0
Prepared 54 packages in 1.14s
Installed 55 packages in 82ms
 + annotated-types==0.7.0

Test Plan

ran locally with output above

[cdoern]

this could be something I am misunderstanding but I don't see how that arg is ever currently used in the way the code is written

[leseb]

I think we should have #1228 merged first and then use this one for the usage examples. Thanks!

[cdoern]

yup, makes sense to me @leseb !

[cdoern]

@leseb rebased ✔️