refactor(walletapi): remove redundant test_connectivity from Notify_broadcaster

[moralpriest]

Remove the go test_connectivity() goroutine from the Notify_broadcaster function in the Height notification handler.

Problem

Notify_broadcaster received a goroutine that called test_connectivity() on every Height notification. This is redundant because:

1. Receiving the notification itself already proves the daemon connection is alive
2. The timer.Reset call at the top of the function already serves as the liveness signal
3. test_connectivity makes additional RPC calls (Echo + GetInfo) that add overhead on every block

Changes

• Remove go test_connectivity() from the Height case in Notify_broadcaster

Notes

• The existing timer.Reset at line 102 handles liveness detection
• Keep_Connectivity watchdog provides the actual dead-connection recovery
• Reduces per-block RPC overhead by 2 calls (Echo + GetInfo)

[Dirtybird99]

Agreed on the redundancy for liveness — timer.Reset(timeout) at the top of Notify_broadcaster already feeds the Keep_Connectivity watchdog.

One consequence to be aware of: test_connectivity is also what refreshes daemon_height/daemon_topoheight (via GetInfo). Registered wallets stay fresh through the sync loop — GetEncryptedBalanceAtTopoHeight(-1) sets daemon_height = result.DHeight on success. But for unregistered wallets that call errors out before the height assignment. So once #30 also removes test_connectivity from the sync loop, an unregistered wallet's daemon_height freezes at its connect-time value (Connect() calls test_connectivity once) — breaking "show chain height while waiting to register" UX.

Suggested fix (here or in #30): update the daemon heights in the unregistered error path of GetEncryptedBalanceAtTopoHeight, or keep a GetInfo on Height notifications when !w.account.Registered.