Do not apply "toLowerCase()" on already lower case canonical form

The canonical form is already in lower case (see
https://webrtc.googlesource.com/src/+/79d8df02/sdk/android/api/org/webrtc/SessionDescription.java#29),
so there is no need to apply "toLowerCase()".

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

app/src/main/java/com/nextcloud/talk/webrtc/PeerConnectionWrapper.java

@@ -494,7 +494,7 @@ public class PeerConnectionWrapper {
 
 
             EventBus.getDefault().post(new SessionDescriptionSendEvent(sessionDescriptionWithPreferredCodec, sessionId,
-                    sessionDescription.type.canonicalForm().toLowerCase(), null, videoStreamType));
+                    sessionDescription.type.canonicalForm(), null, videoStreamType));
 
             if (peerConnection != null) {
                 peerConnection.setLocalDescription(magicSdpObserver, sessionDescriptionWithPreferredCodec);