fix: multiple issues with getting_started notebook (#1795)

Fixes multiple issues 

1. llama stack build of dependencies was breaking with incompatible
numpy / pandas when importing datasets

Moved the notebook to start a local server instead of using library as a
client. This way the setup is cleaner since its all contained and by
using `uv run --with` we can test both the server setup process too in
CI and release time.

2. The change to [1] surfaced some other issues 
- running `llama stack run` was defaulting to conda env name 
- provider data was not being managed properly 
- Some notebook cells (telemetry for evals) were not updated with latest
changes

Fixed all the issues and update the notebook. 

### Test 

1. Manually run it all in local env 
2. `pytest -v -s --nbval-lax docs/getting_started.ipynb`

llama_stack/cli/stack/run.py

@@ -43,7 +43,7 @@ class StackRun(Subcommand):
         self.parser.add_argument(
             "--image-name",
             type=str,
-            default=os.environ.get("CONDA_DEFAULT_ENV"),
+            default=None,
             help="Name of the image to run. Defaults to the current conda environment",
         )
         self.parser.add_argument(