lal python modules go to /usr/local/lib/python3.1x - Ubuntu 22.04 Jammy and Debian 12 Bookworm

From the lal 7.1.7 build log:

checking for /usr/bin/python3 script directory... ${prefix}/local/lib/python3.10/dist-packages
checking for /usr/bin/python3 extension module directory... ${exec_prefix}/local/lib/python3.10/dist-packages

This didn't happen for Debian 10 and 11, and also Ubuntu 20.04 Focal behaved differently.