Deduplicate set of the rtp header extension uri constants

Bug: webrtc:7472
Change-Id: Ic0b4f2cc3374ba70a043310b5046d8bf91f0acbe
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231949
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34990}
diff --git a/call/rtp_video_sender_unittest.cc b/call/rtp_video_sender_unittest.cc
index e58ee3c..29ae311 100644
--- a/call/rtp_video_sender_unittest.cc
+++ b/call/rtp_video_sender_unittest.cc
@@ -103,7 +103,7 @@
   config.rtp.nack.rtp_history_ms = 1000;
   config.rtp.extensions.emplace_back(RtpExtension::kTransportSequenceNumberUri,
                                      kTransportsSequenceExtensionId);
-  config.rtp.extensions.emplace_back(RtpDependencyDescriptorExtension::kUri,
+  config.rtp.extensions.emplace_back(RtpDependencyDescriptorExtension::Uri(),
                                      kDependencyDescriptorExtensionId);
   config.rtp.extmap_allow_mixed = true;
   return config;