message: Remove manual implementaion of the c++17 insert_or_assign
  In favor of the standard one
  Cr-Commit-Position: refs/heads/main@{#35711}
diff: @@ -278,13 +278,7 @@ void RemoteBitrateEstimatorAbsSendTime::IncomingPacketInfo(
  TimeoutStreams(now);
  RTC_DCHECK(inter_arrival_);
  RTC_DCHECK(estimator_);
  - // TODO(danilchap): Replace 5 lines below with insert_or_assign when that
  - // c++17 function is available.
  - auto inserted = ssrcs_.insert(std::make_pair(ssrc, now));
  - if (!inserted.second) {
  - // Already inserted, update.
  - inserted.first->second = now;
  - }
  + ssrcs_.insert_or_assign(ssrc, now);
  // For now only try to detect probes while we don't have a valid estimate.
  // We currently assume that only packets larger than 200 bytes are paced by
  