fix: require a filename for save as dialog

[rmoesbergen]

No description provided.

[sverben]

you can add the required prop on the input element instead of checking in the save method, this will in most browsers also trigger a tooltip indicating you haven't filled out the field, providing additional user feedback

[rmoesbergen]

you can add the required prop on the input element instead of checking in the save method, this will in most browsers also trigger a tooltip indicating you haven't filled out the field, providing additional user feedback

done, still need the return in save() to prevent the dialog from closing when the form is not valid

[koen1711]

Leaving review to @sverben