Invalid visualisation of arguments in payment handlers

[StampixSMO]

Describe the bug
When adding arguments to a payment method handler (for a custom payment plugin), giving the arg json-editor-form-input breaks the UI a bit. See screenshot. The value is saved correctly, the admin UI is just not displaying it correctly.

To Reproduce
Steps to reproduce the behavior:

1. Create a new payment handler with a string arg that uses the json input component

    const handler = new PaymentMethodHandler({
    	  code: 'custom',
    	  args: {
    	    aField: {
    	      type: 'string',
    	      required: true,
    	      ui: {
    	        component: 'json-editor-form-input',
    	      },
    	    },
    	  },
    	...
    });

2. Add the handler to your vendure config
3. Create a new payment in the admin UI
4. Add some JSON to the handler's arguments
5. Save it
6. Refresh the page, the JSON gets displayed as [object Object] and says it's invalid

Expected behavior
The JSON to be displayed properly in the UI.

Environment (please complete the following information):

• @vendure/core version: 3.1.2
• Nodejs version 18
• Database (mysql/postgres etc): postgres