feat: show field coordinates in devmode (#1802)

Show the fields coordinates when the `devmode` search param is present.
It's meant to help API users understand where to position the fields.

packages/ui/primitives/document-flow/add-fields.tsx

@@ -166,7 +166,6 @@ export const AddFieldsFormPartial = ({
 
   const [selectedField, setSelectedField] = useState<FieldType | null>(null);
   const [selectedSigner, setSelectedSigner] = useState<Recipient | null>(null);
-  const [showRecipientsSelector, setShowRecipientsSelector] = useState(false);
   const [lastActiveField, setLastActiveField] = useState<TAddFieldsFormSchema['fields'][0] | null>(
     null,
   );