MAINT: fix umfpack test failure with numpy 1.23
MAINT: fix umfpack test failure with numpy 1.23

The reason is a divide-by-zero warning that our test suite settings
convert to an error. So ignore these warnings, because they're
coming from inside `scikit-umfpack`.

This has been failing consistently in the Azure pre-release job.

Closes gh-16523

[skip github]

Stefan-Endres/scipy,ilayn/scipy,andyfaff/scipy,ilayn/scipy,mdhaber/scipy,endolith/scipy,mdhaber/scipy,ilayn/scipy,ilayn/scipy,endolith/scipy,mdhaber/scipy,rgommers/scipy,ilayn/scipy,mdhaber/scipy,WarrenWeckesser/scipy,endolith/scipy,perimosocordiae/scipy,perimosocordiae/scipy,perimosocordiae/scipy,rgommers/scipy,endolith/scipy,WarrenWeckesser/scipy,scipy/scipy,WarrenWeckesser/scipy,mdhaber/scipy,rgommers/scipy,anntzer/scipy,ilayn/scipy,scipy/scipy,perimosocordiae/scipy,WarrenWeckesser/scipy,andyfaff/scipy,Stefan-Endres/scipy,andyfaff/scipy,WarrenWeckesser/scipy,WarrenWeckesser/scipy,endolith/scipy,anntzer/scipy,anntzer/scipy,endolith/scipy,Stefan-Endres/scipy,andyfaff/scipy,scipy/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,scipy/scipy,andyfaff/scipy,scipy/scipy,perimosocordiae/scipy,rgommers/scipy,mdhaber/scipy,andyfaff/scipy,anntzer/scipy,perimosocordiae/scipy,anntzer/scipy,rgommers/scipy,anntzer/scipy,scipy/scipy