fix potential (not possible for now) issue where we would miss a seeked event
fix potential (not possible for now) issue where we would miss a seeked event

After reading some code, I noticed a - for now impossible - issue
if calling emit_seek_events.ts while the HTMLMediaElement is
already seeking. In that case, we could miss the initial "seeked"
event.

canalplus/rx-player,canalplus/rx-player,canalplus/rx-player,canalplus/rx-player,canalplus/rx-player