Handle custom invalid message when validating forms

Currently, I have this

        "slip": {
            "type": "string",
            "title": "Slip",
            'pattern': '^P(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$',
            "description": "ISO 8601 Duration that allows the start of each run to be as much as the Duration later than their ideal scheduled time. Default is 5 minutes (PT5M)",
            "default": "PT5M",
        },

If i want to add a key such as x-invalid-message: "'%s' is not a valid ISO 8601 duration.", the frontend ignores the validation entirely. It's probably because AJV rejects any unknown keywords in strict mode, breaking all validation.

Perhaps, we'll have to update json-forms-esm and do something like

import { createAjv } from "@jsonforms/core";

const handleDefaultsAjv = createAjv({ useDefaults: true });
handleDefaultsAjv.addKeyword({ keyword: "x-invalid-message" });

Doing this, would then allow us to show better invalid messages to the user.

Currently, in the above case, the UI shows