UBL mesh size

[Playfutbol2]

Using the E5P_UBL_512K_SKRMINIE3 precompiled firmware. G29 P1 does not probe all of the reachable points near the X0 axis and Y0 axis, only the center 17 points. I know that the bltouch cannot probe near the X and Y upper limits, but it should be probing near the lower limits to reduce the number of points that need to be estimated.