tlsturntransport: avoid to call unnecessary callbacks

onStateChanged can be used to just clean some structure, for example
with TlsTurnEndpoint. Also, if called after move, the data can be
scrapped and incorrect.
Also, fix a cast in TlsSocketEndpoint when using ICE.

Change-Id: I8104bc8a0fd8e9cd3dae92e06eee45c22feced45