FS-7513: break is safer than continue

when the encoder returns 0, it means no more data will come and we should not try again

src/mod/applications/mod_conference/mod_conference.c

@@ -1595,7 +1595,7 @@ static void write_canvas_image_to_codec_group(conference_obj_t *conference, code
 			switch_assert((encode_status == SWITCH_STATUS_SUCCESS && frame->m) || !frame->m);
 
 			if (frame->datalen == 0) {
-				continue;
+				break;
 			}
 
 			if (frame->timestamp) {