Use Specific Python Virtual Environment Dependency

## System
- Codeql version: 2.11.2.
- Ubuntu 20.04
- system wide installation in folder (`/home/user/.local/lib/`): `python3.6`, `python3.8`, `python3.10`.
- local python version (virtual environment): `venv38/lib/python3.8/`

## What

I have a bash script that generates the CodeQL database from a specific folder:
```bash
...
# enter in the python3.8 environment with my libraries installed
source venv38/bin/activate
...
# create the db
codeql database create $dataset_path/codeql \
--language=python \
--overwrite \
--source-root=$dataset_raw_files_path
...
```
Output Log:
```txt
...
[2023-09-12 13:54:00] [build-stdout] [INFO] [2] Extracted file /usr/lib/python3.6/tarfile.py in 2036ms
[2023-09-12 13:54:00] [build-stdout] [INFO] [6] Extracted module _md5 in 13ms
[2023-09-12 13:54:00] [build-stdout] [INFO] [3] Extracted file /home/username/.local/lib/python3.6/site-packages/my_fancy_dependency/folder/dependency_file_version_36.py in 352ms
..
```

## Expectation
I would expect codeql to create the db with the custom path to my virtual environment `venv38/lib/python3.8/site-packages/..` and not the system wide python installation: `.local/lib/python3.6`.

**Question**: How can I achieve that? Is there a specific flag or procedure? I cannot find it in the manual [codeql database create](https://docs.github.com/en/code-security/codeql-cli/codeql-cli-manual/database-create)

## Extra Info
1. I need this because the package I need (e.g., in the example the ficticious `my_fancy_dependency`) has a different version for python3.6 (systemwide python installation) and python3.8.
2. I noted that I have other databases which correctly use the right version of python, but it is unclear how they have been created since I have a similar script to generate them from the same folder.

Let me know if you need more info.