CI: Allow numpy without blas when building Linux i686 Py 3.12 wheels
There aren't numpy binary packages for all i686 platforms, so it gets compiled from source. Since version 1.26.0, which is needed for Python 3.12, the compilation fails if libblas is not available. We don't need the speed improvements of libblas for our basic numpy usage.
We specifically install numpy 1.26.1 for Python 3.12 since that is the
version currently in oldest-supported-numpy
.