refactor: harmonize connector iteration to use iterateConnectors() across prod and...

refactor: harmonize connector iteration to use iterateConnectors() across prod and tests

Unify all connector/EVSE iteration patterns behind the iterateConnectors()
generator API, eliminating duplicated if(hasEvses)/else branching in both
production and test code.

Production:
- Refactor getNumberOfConnectors(), hasConnector(),
  getNumberOfReservationsOnConnectorZero() to use iterateConnectors()

Tests:
- Harmonize 10 mock methods in StationHelpers.ts to match production patterns
- Collapse OCPP20TestUtils resetConnectorTransactionState from dual-path to
  single iterateConnectors() loop
- Replace direct evseStatus.connectors map access with getConnectorStatus()
  and getConnectorIdByEvseId() helpers across 4 test files
- Remove redundant EVSE cleanup loops in standardCleanup and fullResetStation
- Align getReservationBy mock signature to production types (ReservationKey)
- Fix alphabetical ordering of mock methods