Fix gridded seismicity focal mechanism assignments
Investigation of #236 (closed) highlights that the focal mechanism ratio applied to point sources generated from optimization tables are wrong. Every point source realized gets the focal mech assigned from the first node in the parent RuptureSet
. It turns out this is about 50/50 SS/R; normal contributes more in eastern California, but normal and reverse hanging wall effects are fairly similar so the net effect on hazard should be small. Unlike #236 (closed), this issue has existed since development of the 2014 CONUS NSHM.