Remove user flag from poetry installation

[geruh]

related to #2425

Rationale for this change

Removing the user flag from the poetry installation to allow users who want to install poetry into a separate dedicated virtual environment.

This virtual environment must be separate from the environment in which we install the iceberg-python repo.

Are these changes tested?

Yes manual testing

> python3 -m venv ~/.venvs/poetry

> source ~/.venvs/poetry/bin/activate

>  echo $VIRTUAL_ENV
/Users/geru/.venvs/poetry

> python -m pip install -U pip setuptools wheel

> poetry --version
Poetry (version 2.1.4)

> poetry show -v
Using virtualenv: /Users/geru/workspace/iceberg-python/.venv

> poetry install
SUCCESS

Are there any user-facing changes?

no

cc: @kevinjqliu

[jayceslesar]

ah I wonder if this has been the source of my issues, I was just manually created a venv with uv, installing poetry and then running make install-dependencies but I imagine this might fix? It also might mess with CI but I suppose we will find out

[kevinjqliu]

thats a good case to check. @jayceslesar can you double check if this resolved your issue?

[jayceslesar]

thats a good case to check. @jayceslesar can you double check if this resolved your issue?

That worked!

[kevinjqliu]

Thanks @geruh and @jayceslesar for verifying :)