Ensure `nMaxOutboundTotalBytesSentInCycle` and `nMaxOutboundCycleStartTime` are initialized even if `CConnman::Start()` is not called. Prevents failures in test/fuzz/connman when run under valgrind.
`nTotalBytesRecv` and `nTotalBytesSent` are already initialized in the class definition, and `CConnman::Start` is only called once in `AppInitMain`, so removing the reinitialization in `Start` has no impact.
This is a backport of core#20408