Km-15482: Fix out-of-order status change

[kp-raafat-alhmidi]

Previously, when a connect attempt failed (e.g. SSL hostname mismatch), the
inner Start{Wireguard,OpenVpn}ConnectionController.handleFailure emitted
Disconnected before the outer StartConnectionController's cleanup path
emitted its own Disconnecting → Disconnected, producing an out-of-order
sequence visible to clients:

Connecting → Disconnected → Disconnecting → Disconnected

Changes:

• Inner Start controllers no longer emit Disconnected on failure; they
  clear cache and rethrow so the outer cleanup path owns the terminal
  status sequence.
• Stop{Wireguard,OpenVpn}ConnectionController now always emit Disconnected
  even when the cleanup chain fails partway (e.g. when stop is invoked
  from the Start failure path before native resources were created), so
  clients always observe a terminal state.

Result: handleConnectionStatusChange(...) sees the canonical
Connecting → Disconnecting → Disconnected(reason) on failure.