Use stepper.get_axis_position_degrees

Marlin/Marlin_main.cpp

   stepper.report_positions();
 
   #if IS_SCARA
-    SERIAL_PROTOCOLPAIR("SCARA Theta:", stepper.get_axis_position_mm(A_AXIS));
-    SERIAL_PROTOCOLLNPAIR("   Psi+Theta:", stepper.get_axis_position_mm(B_AXIS));
+    SERIAL_PROTOCOLPAIR("SCARA Theta:", stepper.get_axis_position_degrees(A_AXIS));
+    SERIAL_PROTOCOLLNPAIR("   Psi+Theta:", stepper.get_axis_position_degrees(B_AXIS));
     SERIAL_EOL;
   #endif
 }