jvb: use JVB_TCP_PORT for exposing the port

JVB_TCP_MAPPED_PORT is the port of on the public
external interface which may be on a completely different server / router.

https://github.com/jitsi/jitsi-videobridge/blob/master/doc/tcp.md

Co-authored-by: Andreas Hansson <andreas.hansson@tritech.se>

docker-compose.yml

@@ -142,7 +142,7 @@ services:
         restart: ${RESTART_POLICY}
         ports:
             - '${JVB_PORT}:${JVB_PORT}/udp'
-            - '${JVB_TCP_MAPPED_PORT}:${JVB_TCP_PORT}'
+            - '${JVB_TCP_PORT}:${JVB_TCP_PORT}'
         volumes:
             - ${CONFIG}/jvb:/config:Z
         environment: