In the Node Version, Flags don't get converted to args

## Describe the bug

I was trying to set chrome `flags` via the node interface and noticed that while they're set as flags in the results' config.js, they don't make it into the args that are used when launching the browser.

This seems to only be true for the node wrapper of the CLI.

For now, work that I'm duplicating the flags into `args` (as an array) before passing config into launchTest and then it gets the flags for launch.

## Steps to reproduce

```
launchTest({
url: 'https://example.com',
browser: 'canary',
flags: '--enable-features=LazyLoadVideoAndAudio'
});
```

## Expected results

What were you expecting to happen?
Flags apply at launch.

## Observed results

flags weren't passed to the CLI

## Additional context

What other information would you like to provide? e.g. screenshots, how you're working around the
issue, or other clues you think could be helpful to identify the root cause.