test: fix Promise rejection was handled asynchronously

[Lightning00Blade]

There were errors coming from this UnitTest

(node:1270676) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 3)
    at handledRejection (node:internal/process/promises:173:23)
    at promiseRejectHandler (node:internal/process/promises:119:7)
    at Promise.then (<anonymous>)
    at Proxy.<anonymous> (/usr/local/google/home/nvitkov/bidi/node_modules/chai-as-promised/lib/chai-as-promised.js:169:53)
    at Proxy.<anonymous> (/usr/local/google/home/nvitkov/bidi/node_modules/chai-as-promised/lib/chai-as-promised.js:47:29)
    at Proxy.methodWrapper (/usr/local/google/home/nvitkov/bidi/node_modules/chai/lib/chai/utils/addMethod.js:57:25)
    at Context.<anonymous> (/usr/local/google/home/nvitkov/bidi/src/cdp/CdpClient.spec.ts:223:53)