[Doc] Suggest "--managed-python" flag when installing python using uv (#33069)

Signed-off-by: Yanwen Lin <lyw1124278064@gmail.com>

docs/getting_started/installation/python_env_setup.inc.md

 It's recommended to use [uv](https://docs.astral.sh/uv/), a very fast Python environment manager, to create and manage Python environments. Please follow the [documentation](https://docs.astral.sh/uv/#getting-started) to install `uv`. After installing `uv`, you can create a new Python environment using the following commands:
 
 ```bash
-uv venv --python 3.12 --seed
+uv venv --python 3.12 --seed --managed-python
 source .venv/bin/activate
 ```