chore!: remove --image-type and --image-name from llama stack run (#3714)

# What does this PR do?
Simplifies the CLI. I don't think these options make sense anymore: only
venv is supported as image-type, and users can simply activate the env
before running `llama stack` as they do any other project.

## Test Plan





---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
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[ReviewStack](https://reviewstack.dev/llamastack/llama-stack/pull/3714).
* __->__ #3714
* #3711

.github/workflows/integration-auth-tests.yml

@@ -86,7 +86,7 @@ jobs:
 
           # avoid line breaks in the server log, especially because we grep it below.
           export COLUMNS=1984
-          nohup uv run llama stack run $run_dir/run.yaml --image-type venv > server.log 2>&1 &
+          nohup uv run llama stack run $run_dir/run.yaml > server.log 2>&1 &
 
       - name: Wait for Llama Stack server to be ready
         run: |

.github/workflows/test-external-provider-module.yml

@@ -59,7 +59,7 @@ jobs:
           # Use the virtual environment created by the build step (name comes from build config)
           source ramalama-stack-test/bin/activate
           uv pip list
-          nohup llama stack run tests/external/ramalama-stack/run.yaml --image-type ${{ matrix.image-type }} > server.log 2>&1 &
+          nohup llama stack run tests/external/ramalama-stack/run.yaml > server.log 2>&1 &
 
       - name: Wait for Llama Stack server to be ready
         run: |

.github/workflows/test-external.yml

@@ -59,7 +59,7 @@ jobs:
           # Use the virtual environment created by the build step (name comes from build config)
           source ci-test/bin/activate
           uv pip list
-          nohup llama stack run tests/external/run-byoa.yaml --image-type ${{ matrix.image-type }} > server.log 2>&1 &
+          nohup llama stack run tests/external/run-byoa.yaml > server.log 2>&1 &
 
       - name: Wait for Llama Stack server to be ready
         run: |