I.seeInField() not accepting the locators having underscore in FireFox

I.seeInField() method should accept the locators having underscore

It gives following error

```
unknown variant `css`, expected one of `css selector`, `link text`, `partial link text`, `tag name`, `xpath` at line 1 column 14

* CodeceptJS version: 2.6.5
* NodeJS Version: 10.16.0
* Operating System: windows 10
* puppeteer || webdriverio || protractor || testcafe version (if related) webdriverio
* Configuration file:

```js
# paste config here
```