Low-priority homing in G34 (#14391)

Marlin/src/gcode/calibrate/G34_M422.cpp

     );
 
     // Home before the alignment procedure
-    home_all_axes();
+    if (homing_needed()) home_all_axes();
 
     // Move the Z coordinate realm towards the positive - dirty trick
     current_position[Z_AXIS] -= z_probe * 0.5;