Fix start g-code of Monoprice Select Mini v2

Apparently the original start code caused it to move outside the build volume or beyond the limit in the Y direction.

Fixes #3924.

resources/definitions/monoprice_select_mini_v2.def.json

@@ -20,6 +20,10 @@
 
     "overrides": {
         "machine_name": { "default_value": "Monoprice Select Mini V2" },
+        "machine_end_gcode":
+        {
+            "default_value": "G0 X0 Y120;(Stick out the part)\nM190 S0;(Turn off heat bed, don't wait.)\nG92 E10;(Set extruder to 10)\nG1 E7 F200;(retract 3mm)\nM104 S0;(Turn off nozzle, don't wait)\nG4 S300;(Delay 5 minutes)\nM107;(Turn off part fan)\nM84;(Turn off stepper motors.)"
+        },
         "adhesion_type": { "default_value": "brim" },
         "retraction_combing": { "default_value": "noskin" },
         "retraction_amount" : { "default_value": 2.5},