Should the FileUpload have required and readOnly?

[bjosttveit]

Description

The FileUpload and FileUploadWithTag components both have required and readOnly properties from the default FormComponentProps. For these components required does not really make sense, and is not used for anything other than incidentally setting a required * marker next to the title. It should rather behave more similar to RepeatingGroup which get it set based on if minCount > 0. We should remove the required property since it has no real effect.

As for readOnly, there is no visual indication that the component is read only. It only blocks the user from uploading without any explanation. I am not sure what the purpose of a readOnly file upload could possibly be, but if we need to keep it, it should be indicated better, and probably not show a "file drop zone" at all.

[bjosttveit]

Adding milestone v5 as removing props could be breaking