fix: Allow adding JSON fields via Customize Form

frappe/custom/doctype/custom_field/custom_field.json

@@ -123,7 +123,7 @@
    "label": "Field Type",
    "oldfieldname": "fieldtype",
    "oldfieldtype": "Select",
-   "options": "Autocomplete\nAttach\nAttach Image\nBarcode\nButton\nCheck\nCode\nColor\nColumn Break\nCurrency\nData\nDate\nDatetime\nDuration\nDynamic Link\nFloat\nFold\nGeolocation\nHeading\nHTML\nHTML Editor\nIcon\nImage\nInt\nLink\nLong Text\nMarkdown Editor\nPassword\nPercent\nRead Only\nRating\nSection Break\nSelect\nSmall Text\nTable\nTable MultiSelect\nText\nText Editor\nTime\nSignature\nTab Break",
+   "options": "Autocomplete\nAttach\nAttach Image\nBarcode\nButton\nCheck\nCode\nColor\nColumn Break\nCurrency\nData\nDate\nDatetime\nDuration\nDynamic Link\nFloat\nFold\nGeolocation\nHeading\nHTML\nHTML Editor\nIcon\nImage\nInt\nJSON\nLink\nLong Text\nMarkdown Editor\nPassword\nPercent\nRead Only\nRating\nSection Break\nSelect\nSignature\nSmall Text\nTab Break\nTable\nTable MultiSelect\nText\nText Editor\nTime",
    "reqd": 1
   },
   {
@@ -439,7 +439,7 @@
  "idx": 1,
  "index_web_pages_for_search": 1,
  "links": [],
- "modified": "2022-02-28 22:22:54.893269",
+ "modified": "2022-04-14 09:46:58.849765",
  "modified_by": "Administrator",
  "module": "Custom",
  "name": "Custom Field",