fix: made is_system_generated hidden in customize form field doctype

frappe/custom/doctype/customize_form_field/customize_form_field.json

@@ -450,6 +450,7 @@
    "default": "0",
    "fieldname": "is_system_generated",
    "fieldtype": "Check",
+   "hidden": 1,
    "label": "Is System Generated",
    "read_only": 1
   }
@@ -458,7 +459,7 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2022-03-31 11:27:05.269293",
+ "modified": "2022-03-31 12:05:11.799654",
  "modified_by": "Administrator",
  "module": "Custom",
  "name": "Customize Form Field",