Improve handling of timeouts when calling onNewTxRequest

[tuliomir]

On testnet, we received the following error:

022-06-21T02:37:20.481Z [wallet-service-daemon] error: Unexpected token u in JSON at position 0 
Stack: 'SyntaxError: Unexpected token u in JSON at position 0
at JSON.parse (<anonymous>)
at Response.<anonymous> (/app/hathor-wallet-service-sync_daemon.cjs.production.min.js:1:12602)
at Request.<anonymous> (/app/node_modules/aws-sdk/lib/request.js:367:18)
at Request.callListeners (/app/node_modules/aws-sdk/lib/sequential_executor.js:106:20)
at Request.emit (/app/node_modules/aws-sdk/lib/sequential_executor.js:78:10)
at Request.emit (/app/node_modules/aws-sdk/lib/request.js:686:14)
at Request.transition (/app/node_modules/aws-sdk/lib/request.js:22:10)
at AcceptorStateMachine.runTo (/app/node_modules/aws-sdk/lib/state_machine.js:14:12)
at /app/node_modules/aws-sdk/lib/state_machine.js:26:10
at Request.<anonymous> (/app/node_modules/aws-sdk/lib/request.js:38:9)' 
}

Probably we received an undefined as a response instead of a valid JSON, and that crashed the process. On further investigation a timeout in the OnNewTxRequest was probably the reason, causing the Daemon to receive nothing as response.

It would be important to add more context metadata to this error handling for faster pinpointing of the error cause.