The switching of icons didn't work on the iPad anymore (See
https://norden.social/@betamax65/110088664994961476). This might be a temporary
fix, depending on what caused the bug (which I couldn't determine). For now,
one icon in the set seemingly must have a complete iPad icon set, which is
achieved with the standard icon. Furthermore, an assert statement helps to
determine the problem with the icons. This statement won't be compiled into
release builds.
Signed-off-by: Paul Schuetz <pa.schuetz@web.de>
