Default JSON Schema type validation does not take to account whether a field is required

[Chalolennox]

Description
I am playing around with the json schema examples(https://formly.dev/docs/examples/advanced/json-schema) and realised the schema depedency example with bootstrap does not set validation on the field credit_card correctly when I clear the input after typing in a value. This field is optional. I suspect the validator for number type is active.

Minimal Reproduction

{
    "title": "Schema dependencies",
    "description": "These samples are best viewed without live validation.",
    "type": "object",
    "properties": {
        "simple": {
            "title": "Simple",
            "type": "object",
            "properties": {
                "credit_card": {
                    "type": "number",
                    "title": "Credit card"
                }
            },
            "dependencies": {
                "credit_card": {
                    "properties": {
                        "billing_address": {
                            "type": "string",
                            "title": "Billing address"
                        }
                    },
                    "required": [
                        "billing_address"
                    ]
                }
            }
        }
    }
}

I have tried the react version of the library on https://rjsf-team.github.io/react-jsonschema-form/ and it works as intended in that when I clear the credit_card field, the form is valid again. As soon as I type a value and clears it, formly shows a validation error. Here is the active validator:

({
        value
      }) => {
        if (value === void 0) {
          return true;
        }
        if (value === null && types.indexOf("null") !== -1) {
          return true;
        }
        switch (types[0]) {
          case "null": {
            return typeof value === null;
          }
          case "string": {
            return typeof value === "string";
          }
          case "integer": {
            return isInteger(value);
          }
          case "number": {
            return typeof value === "number";
          }
          case "object": {
            return isObject(value);
          }
          case "array": {
            return Array.isArray(value);
          }
        }
        return true;
      }

is there a better way to deal with nullable values which are not required when validating?

[Chalolennox]

A work around would be to extend formlyJsonschema.toFieldConfig