fix(ui): allow json fields to be updated externally (#11371)

### What?
Unable to update json fields externally. For example, calling `setValue`
on a json field would not be reflected in the admin panel UI.

### Why?
JSON fields use the monaco editor to manage state internally, so
programmatically updating the value in state does not change the
internal value.

### How?
Set a ref when the user updates the value and then unset the ref after
the change is complete.

Inside the hook that watches `value`, if the value changed and the
change came from the system (i.e. a programmatic change) refresh the
editor by adjusting its key prop. If the change was made by the user,
there is no need to refresh the editor.

Fixes https://github.com/payloadcms/payload/issues/10819

test/fields/payload-types.ts

@@ -1474,6 +1474,15 @@ export interface JsonField {
       | boolean
       | null;
   };
+  customJSON?:
+    | {
+        [k: string]: unknown;
+      }
+    | unknown[]
+    | string
+    | number
+    | boolean
+    | null;
   updatedAt: string;
   createdAt: string;
 }
@@ -3165,6 +3174,7 @@ export interface JsonFieldsSelect<T extends boolean = true> {
     | {
         jsonWithinGroup?: T;
       };
+  customJSON?: T;
   updatedAt?: T;
   createdAt?: T;
 }