Remove self assignment in if-clause

Follow-up to https://webrtc-review.googlesource.com/c/src/+/360460

Bug: chromium:361594695
Change-Id: Id41d964871aa1c074145901af275b0fe004b8e7b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/361340
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42919}

sdk/objc/api/peerconnection/RTCIceCandidateErrorEvent.mm

@@ -29,7 +29,8 @@
                             url:(const std::string&)url
                       errorCode:(const int)errorCode
                       errorText:(const std::string&)errorText {
-  if (self = [self init]) {
+  self = [self init];
+  if (self) {
     _address = [NSString stringForStdString:address];
     _port = port;
     _url = [NSString stringForStdString:url];