can.viewer increments count and reset dt when scroll is used  #1407

Describe the bug

every time the function 'scroll' is used, either with the keyboard or the mouse wheel, Count value is increased, and dt value is reset.

To Reproduce

• Start can.viewer as usual : python -m can.viewer -c can0 -i socketcan -b 1000000
• Reduce the size of the terminal in order to have more frames than the terminal can show.
• Used the scroll function, with up or down key, or with the mouse wheel

Expected behavior

Count and dt values doesn't changed on scroll

Additional context

OS and version:Fedora 36
Python version:3.10.7
python-can version:4.0.0
python-can interface/s (if applicable):socketcan