Crash (or broken rendering) when using a non-HDR texture as lightProbe

Switch a light probe from a .hdr file to a .png. The result is a crash since the loaded RGB(A) QImage data will be used in combination with the RGBA16F format, as if it was .hdr.

It may not make much sense to try using ordinary rgba images for IBL and skyboxes, but at least it should not crash.

When fixing the crash the rendered results are less than ideal so there are further issues here than just crashing. Perhaps there are floating point assumptions elsewhere too.