chore!: remove --env from llama stack run (#3711)

# What does this PR do?
user can simply set env vars in the beginning of the command.`FOO=BAR
llama stack run ...`

## Test Plan
Run
TELEMETRY_SINKS=coneol uv run --with llama-stack llama stack build
--distro=starter --image-type=venv --run




---
[//]: # (BEGIN SAPLING FOOTER)
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[ReviewStack](https://reviewstack.dev/llamastack/llama-stack/pull/3711).
* #3714
* __->__ #3711

docs/getting_started_llama4.ipynb

@@ -233,12 +233,12 @@
         "  del os.environ[\"UV_SYSTEM_PYTHON\"]\n",
         "\n",
         "# this command installs all the dependencies needed for the llama stack server\n",
-        "!uv run --with llama-stack llama stack build --distro meta-reference-gpu --image-type venv\n",
+        "!uv run --with llama-stack llama stack build --distro meta-reference-gpu\n",
         "\n",
         "def run_llama_stack_server_background():\n",
         "    log_file = open(\"llama_stack_server.log\", \"w\")\n",
         "    process = subprocess.Popen(\n",
-        "        f\"uv run --with llama-stack llama stack run meta-reference-gpu --image-type venv --env INFERENCE_MODEL={model_id}\",\n",
+        "        f\"INFERENCE_MODEL={model_id} uv run --with llama-stack llama stack run meta-reference-gpu\",\n",
         "        shell=True,\n",
         "        stdout=log_file,\n",
         "        stderr=log_file,\n",