Rename AppRequestFailed to AppError (#2321)

Signed-off-by: Joshua Kim <20001595+joshua-kim@users.noreply.github.com>

Author: joshua-kim

proto/p2p/p2p.proto

@@ -58,7 +58,7 @@ message Message {
     AppGossip app_gossip = 32;
 
     PeerListAck peer_list_ack = 33;
-    AppRequestFailed app_request_failed = 34;
+    AppError app_error = 34;
   }
 }
 
@@ -387,7 +387,7 @@ message Chits {
 // AppRequest is a VM-defined request.
 //
 // Remote peers must respond to AppRequest with a corresponding AppResponse or
-// AppRequestFailed
+// AppError
 message AppRequest {
   // Chain being requested from
   bytes chain_id = 1;
@@ -409,8 +409,8 @@ message AppResponse {
   bytes app_bytes = 3;
 }
 
-// AppRequestFailed is a VM-defined error sent in response to AppRequest
-message AppRequestFailed {
+// AppError is a VM-defined error sent in response to AppRequest
+message AppError {
   // Chain the message is for
   bytes chain_id = 1;
   // Request id of the original AppRequest