[Feature] Ignore generating markers past end

[feederbox826]

Is your feature request related to a problem? Please describe.
When generating markers, the duration of the file is not considered. This leads to errors generating these markers with the following ffmpeg error

[generator] failed to generate marker screenshot: ffmpeg command produced no output

This is the correct response, as these markers are impossible to generate given the file

Describe the solution you'd like
When generating markers, start times past the duration of the file are ignored

Describe alternatives you've considered
Removing these markers is possible via [Skip Sync] and the corresponding TMDB skip sync tags

Additional context
This change could also be made on the marker sync side but I don't believe duration of the file is associated with the markers. In addition, scrapers can also generate invalid marker timestamps