feat: Add 'required' property to ion-checkbox and ion-radio

### Prerequisites

- [X] I have read the [Contributing Guidelines](https://github.com/ionic-team/ionic-framework/blob/main/.github/CONTRIBUTING.md#creating-an-issue).
- [X] I agree to follow the [Code of Conduct](https://ionicframework.com/code-of-conduct).
- [X] I have searched for [existing issues](https://github.com/ionic-team/ionic-framework/issues) that already include this feature request, without success.

### Describe the Feature Request

When trying to set an ion-checkbox or ion-radio to 'required' I get "Property 'required' does not exist on type 'IonRadio & HTMLAttributes'."

### Describe the Use Case

I have checkboxes and radio buttons in my form which need to be validated on if they're checked.

### Describe Preferred Solution

_No response_

### Describe Alternatives

_No response_

### Related Code

` this.nativeInput = el}
value={value}
required={this.required}
/>`

` this.nativeInput = el}
value={value}
required={this.required}
/>`

### Additional Information

_No response_

Start by locating the ion-checkbox and ion-radio component entry points and their generated TypeScript declarations. Trace how the existing name, disabled, checked, and value properties are exposed, then determine where the required property belongs. Done means the property is accepted on both components and supports the requested form-validation use case.

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