Steps to reproduce

Create a survey with a file upload question. Try to upload a file using only the keyboard.

Expected result

When I press the file select button in the file upload modal via keyboard, the file input should open. You could add a javascript listener on the button and click the actual file input programmatically. This also means you would not have to position the file input invisibly above the button, which would prevent issues if the button changes size due to theming.

Actual result

When I press the file select button via keyboard nothing happens. ( And when I style the button to be bigger, the file input only partially overlaps the button, leading to weird behaviour where the user correctly presses the button but does not hit the invisble file input element).