Revert "libsigc++ 2.3.1"

2.3.x is a development branch.

This reverts commit 512e05bebeec754416f5bb7b9aa0f95cf5c1d963.

Closes #31864.
libsigc++: update 2.2.11 bottle.
net6: clean up install
libtasn1 4.1
libtasn1: update 4.1 bottle.