fix ErrRTPTransceiverNotExisted typo

Author: yngrtc

rtc-shared/src/error.rs

@@ -1591,8 +1591,8 @@ pub enum Error {
     ErrRTPSenderDTLSTransportNil,
     #[error("Send has already been called")]
     ErrRTPSenderSendAlreadyCalled,
-    #[error("TPTransceiver not existed")]
-    ErrTPTransceiverNotExisted,
+    #[error("RTPTransceiver not existed")]
+    ErrRTPTransceiverNotExisted,
     #[error("errRTPSenderTrackNil")]
     ErrRTPTransceiverCannotChangeMid,
     #[error("invalid state change in RTPTransceiver.setSending")]