Revert "Don't crash when a datachannel can't get an ID"

This reverts commit 77c442ca1946924b0acfc9c0ba469ef6a2c3178f.

Reason for revert: Breakage on internal build tests, random breakage elsewhere. Timing issues suspected.

Original change's description:
> Don't crash when a datachannel can't get an ID
> 
> This is exercised by WPT test RTCDataChannel-id.
> 
> Bug: chromium:945256
> Change-Id: I53781dc874134f8c68a49c201848377b93b8858f
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128871
> Reviewed-by: Henrik Boström <hbos@webrtc.org>
> Reviewed-by: Seth Hampson <shampson@webrtc.org>
> Commit-Queue: Harald Alvestrand <hta@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#27300}

TBR=hbos@webrtc.org,hta@webrtc.org,shampson@webrtc.org

Change-Id: Ib7eaf8880e8ce21226b84b3b2283be93acb8dc8b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:945256
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/129766
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27302}
diff --git a/pc/data_channel.cc b/pc/data_channel.cc
index a554829..e4727f2 100644
--- a/pc/data_channel.cc
+++ b/pc/data_channel.cc
@@ -414,10 +414,7 @@
   if (!writable) {
     return;
   }
-  // If the datachannel has not been assigned an ID, ignore update.
-  if (id() < 0) {
-    return;
-  }
+
   SendQueuedControlMessages();
   SendQueuedDataMessages();
   UpdateState();