Float XY probe offset followup (probe edge) (#15928)

Marlin/src/gcode/bedlevel/abl/G29.cpp

       ABL_VAR xy_uint8_t meshCount;
     #endif
 
-    ABL_VAR xy_int_t probe_position_lf, probe_position_rb;
+    ABL_VAR xy_float_t probe_position_lf, probe_position_rb;
     ABL_VAR xy_float_t gridSpacing = { 0, 0 };
 
     #if ENABLED(AUTO_BED_LEVELING_LINEAR)