Update session recording playback progress during large frame gaps

Currently the in-browser session recording player only updates the progress bar and elapsed timer when a new frame is rendered.

For most recordings, this isn't really an issue since there are frequent frames, but there's nothing technically stopping recordings from having arbitrarily long gaps between frames, and this does sometimes happen in practice.

The session recording player should be modified to always update the progress at a reasonable rate (e.g. 1hz) and also allow seeking to arbitrary positions between frames.