Enlarge the file browser modal to use screen space

This is partially a problem due to having a large screen, but the current file browser is only showing 7 files at the same time which is rather annoying in large directories. It would be very useful if it would use a larger portion of my display.

To illustrate, here’s a partial screenshot:

For now I have fixed it with the following user-css:

        height: 90%;

But I’m guessing that won’t work for long since the obviously randomly generated name in the css classes will probably change with every release.