avfvideosrc: fix wrong framerate selected for caps
Some USB webcams and HDMI capture devices provide different formats that support different framerate ranges for the same resolution. Currently, avfvideosrc has an issue where it selects a format that doesn't support the requested framerate if a previous format that supports it was found. This meant that avfvideosrc would output a video source that didn't respect the requested framerate.
This merge request solves that issue. Tested on a mac mini M1 using the following capture devices:
- Logitech Webcam C930e
- Macrosilicon MS2109 HDMI to USB Before applying the fix, requesting a framerate of 30/1 would only output around 5fps.
Please consider backporting this to 1.20.