write correct value to native input node on visibility toggle

[oktav777]

When input visibility is manipulated by angular renderer, for example hide/show using *ngIf, it will write to the native HTMLInputElement.value the FileInput object from the @Input() value instead of the array of files.

The PR will fix the issue by verifying the type of object before assigning the to the native input value.

[merlosy]

I think this one deserves some thinking.
First, I think this is breaking the current behavior.
Second, native type for <input type=file> is of type FileList, whose File objects are accessible through the files property. So it doesn't seem a native thing to read the array of files directly from the model value.

If this is really an issue please provide a repro case on stackblitz or implements a test case that emphasize the wrong behavior.

[oktav777]

Take a look at this demo
Here are the steps to reproduce:

1. Fill the file input.
2. Hit the toggle button, this will hide it from the DOM.
3. Hit again toggle, it will error and the file input will 'lose' it's value.

You can perform this action on the text input and you will see that after re-appearing in DOM, text input will preserve it's value. As I see this is the behavior of the ControlValueAccessor.

[merlosy]

Test are ok.

[merlosy]

Tested and it seems to be ok.
Thanks for the PR