scaling issue in player

from https://github.com/bavc/qctools/pull/729

I see one more player layout error:

• open a 4/3 file
• enable 2nd filter (defaults to waveform), looks like
• switch mode to "Free Scale" and resize with slider and then set back to "Fit to Screen", image should be same as end of last step
• enable the third filter (defaults to bitplane), and then it looks like
• can fix with toggle to "Free Scale" and back to "Fit to Screen"

btw: these tests ^^^ were with the qt5 build env