Re-enable temporarily disabled header extension test.

The expected exception type is updated to match the spec and the newly
rolled WebRTC CL.

Bug: chromium:1051821
Change-Id: Ie4244767871a83395df81d92ec0e111f65550bde
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4320705
Reviewed-by: Philipp Hancke <phancke@microsoft.com>
Commit-Queue: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1115036}

webrtc-extensions/RTCRtpTransceiver-headerExtensionControl.html

@@ -57,10 +57,10 @@
   const transceiver = pc.addTransceiver('audio');
   const capabilities = transceiver.getHeaderExtensionsToNegotiate();
   capabilities[0].uri = "4711";
-  assert_throws_dom("NotSupportedError", () => {
+  assert_throws_dom('InvalidModificationError', () => {
     transceiver.setHeaderExtensionsToNegotiate(capabilities);
-  }, 'transceiver should throw NotSupported when setting an unknown URI');
-}, `setHeaderExtensionsToNegotiate throws NotSupported on encountering unknown URI`);
+  }, 'transceiver should throw InvalidModificationError when setting an unknown URI');
+}, `setHeaderExtensionsToNegotiate throws InvalidModificationError on encountering unknown URI`);
 
 test(function(t) {
   const pc = new RTCPeerConnection();
@@ -72,7 +72,7 @@
   });
   ["sendonly", "recvonly", "inactive", "stopped"].map(direction => {
     capability.direction = direction;
-    assert_throws_dom("InvalidModificationError", () => {
+    assert_throws_dom('InvalidModificationError', () => {
       transceiver.setHeaderExtensionsToNegotiate(capabilities);
     }, `transceiver should throw InvalidModificationError when setting a mandatory header extension\'s direction to ${direction}`);
   });