Fix pip installs in GitHub Actions

[jiridanek]

The pip install command now requires passing --break-system-packages, otherwise it refuses the install.
To solve this, it's best to install with pipx.

In addition, this commit removes cache for pip install poetry, because the speedup is minimal and totally not worth the effort.

• 'This environment is externally managed' python error actions/runner-images#8615

Run python -m pip install --upgrade pip
error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
    python3-xyz, where xyz is the package you are trying to
    install.
    
    If you wish to install a non-Debian-packaged Python package,
    create a virtual environment using python3 -m venv path/to/venv.
    Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
    sure you have python3-full installed.
    
    If you wish to install a non-Debian packaged Python application,
    it may be easiest to use pipx install xyz, which will manage a
    virtual environment for you. Make sure you have pipx installed.
    
    See /usr/share/doc/python3.[1](https://github.com/red-hat-data-services/ods-ci/actions/runs/11324701737/job/31490057077#step:3:1)2/README.venv for more information.

note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.
hint: See PEP [6](https://github.com/red-hat-data-services/ods-ci/actions/runs/11324701737/job/31490057077#step:3:7)68 for the detailed specification.
Error: Process completed with exit code 1.

from https://github.com/red-hat-data-services/ods-ci/actions/runs/11324701737/job/31490057077

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %
545	0	0	545	100

[jstourac]

thanks!