Increase warning temperature for initial layer as well

It was already changed for normal printing temperature.

Contributes to issue CURA-3433.

resources/definitions/fdmprinter.def.json

@@ -1300,7 +1300,7 @@
                     "value": "material_print_temperature",
                     "minimum_value": "-273.15",
                     "minimum_value_warning": "0",
-                    "maximum_value_warning": "260",
+                    "maximum_value_warning": "270",
                     "enabled": "machine_gcode_flavor != \"UltiGCode\"",
                     "settable_per_mesh": false,
                     "settable_per_extruder": true