Updating binary data in the frontend application does not trigger validations on the backend

### Description of the bug

Frontend does not set `ignoredFileValidators` on binary data update, which means the backend does not run validators when the only change is the user adding or removing a file in the "FileUpload" element.
Technical details are discussed and expanded upon here: https://digdir-samarbeid.slack.com/archives/C02EJ9HKQA3/p1750082734040659

### Steps To Reproduce

1. Make a frontend application with a FileUpload element with "showValidations":["CustomBackend"]
2. Make a validator class that implements IValidator in the backend
3. Observe that the validator does not run when user adds or removes a file in the FileUpload element.

### Additional Information

_No response_

Start by tracing binary-data updates from the FileUpload element and inspect where ignoredFileValidators is set. Reproduce the case with showValidations set to CustomBackend and a backend validator implementing IValidator. Done means the validator runs when a user adds or removes a file without other changes.

Written by the indexing model from the issue text.