fix: remove explicit sabyenc pip install (incompatible with Python 3.13)

sabyenc uses deprecated Python 2 C API (PyString_*) removed in Python
3.12+. Debian Trixie ships Python 3.13. The yEnc dependency is handled
by SABnzbd's requirements.txt. Remove the outdated explicit pip install.

Dockerfile

@@ -27,11 +27,9 @@ RUN export SABNZBD_VERSION=3.7.2 PAR2CMDLINE_VERSION=v0.6.14-mt1 && \
     export PIP_BREAK_SYSTEM_PACKAGES=1 && \
     export BUILD_PACKAGES="automake build-essential python3-dev libffi-dev" && \
     export RUNTIME_PACKAGES="ca-certificates p7zip-full unrar unzip libgomp1 openssl python3-openssl curl python3-pip" && \
-    export PIP_PACKAGES="sabyenc" && \
     sed -i "s/Components: main/Components: main contrib non-free/" /etc/apt/sources.list.d/debian.sources && \
     apt-get -qq update && \
     apt-get -qq --yes install $BUILD_PACKAGES $RUNTIME_PACKAGES && \
-    pip3 install $PIP_PACKAGES && \
     curl -SL -o /tmp/sabnzbd.tar.gz https://github.com/sabnzbd/sabnzbd/releases/download/${SABNZBD_VERSION}/SABnzbd-${SABNZBD_VERSION}-src.tar.gz && \
     tar xzf /tmp/sabnzbd.tar.gz && \
     mv SABnzbd-* sabnzbd && \