fix(docker): pin Poetry to 2.2.1 for Python 3.9 compatibility (#8735)

Poetry 2.3.0 dropped Python 3.9 support. Without cache the installer
fetches the latest version (currently 2.3.2), which fails on the
python:3.9-slim-bookworm base image. Pin to 2.2.1, the last release
compatible with Python 3.9.

Co-authored-by: Rodrigo Silva <rodrigo.silva@bonial.com>

Author: 2 people

backend/Dockerfile

@@ -149,7 +149,7 @@ RUN python3 -m pip install --no-cache --upgrade pip setuptools && \
     python3 -m pip install --upgrade pip
 
 # Setup Python Poetry package manager
-RUN curl -sSL https://install.python-poetry.org | python3 -
+RUN curl -sSL https://install.python-poetry.org | python3 - --version 2.2.1
 ENV PATH="$PATH:/app/.local/bin"
 
 # Build Python plugins, make sure the scripts has execute permission