fix: сallback was already called

[strophy]

Smoke tests were returning errors in CI:

Error: Callback was already called.
    at /usr/src/app/node_modules/async/dist/async.js:321:36
    at newCallback (/usr/src/app/node_modules/@dashevo/dashd-rpc/lib/index.js:59:7)
    at ClientRequest.<anonymous> (/usr/src/app/node_modules/@dashevo/dashd-rpc/lib/index.js:146:7)
    ...

Use of the debugger revealed information about the request/response sent in the first callback function, and timeout messages being sent to the callback function in a second run. This PR fixes it, although I'm not entirely sure if this is how the called variable is supposed to be used.

[shumkov]

👍