javascript error: Cannot convert undefined or null to object

Hey, after updating `electron` to v10 and `spectron` to v12 I've started having issues with running my test suite. So I started debugging by creating a single test with code taken from spectron's readme. And when trying to run this test (I'm using Jest by the way) I get this error:

```
javascript error: javascript error: Cannot convert undefined or null to object
(Session info: chrome=85.0.4183.98)

at getErrorFromResponseBody (node_modules/webdriver/build/utils.js:121:10)
at WebDriverRequest._request (node_modules/webdriver/build/request.js:149:56)
at Browser.wrapCommandFn (node_modules/@wdio/utils/build/shim.js:74:23)
at Browser.wrapCommandFn (node_modules/@wdio/utils/build/shim.js:74:23)
```

Application window launches however, the test fails

- Node: v14.10.1
- spectron: 12.0.0
- electron: v10.1.2
- chromedriver: 85.0.4183.98

Start by reproducing the single Jest test based on the Spectron README with Electron 10, Spectron 12, Node 14, and ChromeDriver 85. Read the reported stack locations in node_modules/webdriver/build/utils.js, node_modules/webdriver/build/request.js, and node_modules/@wdio/utils/build/shim.js. Done means the README-based test runs without the reported null-or-undefined conversion error.

Written by the indexing model from the issue text.