Changed warning value prime tower purge

Increased the value after tests show 1mm3+ primes don't lead to issues.

resources/definitions/fdmprinter.def.json

@@ -4908,7 +4908,7 @@
                     "unit": "mm³",
                     "default_value": 0,
                     "minimum_value": "0",
-                    "maximum_value_warning": "1",
+                    "maximum_value_warning": "2.5",
                     "settable_per_mesh": false,
                     "settable_per_extruder": true
                 },