Remove the possibility to disable IPv6 in Java and ObjC.

It's deprecated and has been removed from Chrome. Let's follow suite.

// Passing all but unrelated bots
NOTRY=True

Bug: webrtc:14608
Change-Id: I6f2601af5b1dc08164230ebf15db2d2f1754f9e5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/280740
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38488}
diff --git a/api/peer_connection_interface.h b/api/peer_connection_interface.h
index 4db89a3..55300a5 100644
--- a/api/peer_connection_interface.h
+++ b/api/peer_connection_interface.h
@@ -427,8 +427,7 @@
     //////////////////////////////////////////////////////////////////////////
 
     // If set to true, don't gather IPv6 ICE candidates.
-    // TODO(https://crbug.com/1315576): Remove the ability to set it in Chromium
-    // and delete this flag.
+    // TODO(https://crbug.com/webrtc/14608): Delete this flag.
     bool disable_ipv6 = false;
 
     // If set to true, don't gather IPv6 ICE candidates on Wi-Fi.