MOHAWK: RIVEN: Rewind videos that are played until their end

When videos are skipped, they would sometimes not quite be seeked to the
last frame. In that case, when they are played again without being
restarted, they would end immediatly.

Now videos are automatically rewinded when they end or are skipped so
that they always start from the beginning when played again.

Fixes #10389.

engines/mohawk/riven_video.cpp

@@ -255,6 +255,7 @@ void RivenVideo::playBlocking(int32 endTime) {
 	if (playTillEnd) {
 		disable();
 		stop();
+		seek(0);
 	}
 
 	// Execute the stored opcode