Fixed file input value when used on forms

[aidamag]

Checklist
(Check off all the items before submitting)

• Build process is done without errors and all tests pass in /lib directory.
• Self-reviewed the code prior to submitting.
• Meets accessibility standards.
• Added/updated documentation to /website as needed.
• Added/updated tests as needed.

Description

• Added name prop to hidden input, disabled, aria-hidden and readOnly as in the rest of the components that use hidden inputs.
• Updated style to display: none as in the rest of the components.
• Added test to check that the component is sending value when submitting with form.

Closes #1351