fix(ocpp-wamp): OkHttp client reports a connection failure as a connection lost #148

OkHttpOcppWampClient.onFailure (OkHttpOcppWampClient.kt:180-182) sets
connectionState = DISCONNECTED before testing connectionState == CONNECTING. The test is
therefore always false: a failure during connection is reported as onConnectionLost instead of
onConnectionFailure, and logged as "failure with connection".

tryToConnect still completes, because its onConnectionLost counts down the latch "just in
case", but the listener contract (ConnectionListener.onConnectionFailure) is never honoured on
that path.

Found while working on #108 (PR #147).