fix(typings): ensure WDIO methods return Promise

[abdel-ships-it]

This is almost the same change as #962, but against the v3. This will ensure older versions of the framework still get the correct async matchers signature. This is inline with how the v3 branch is documented with toBeDisplayed getting awaited.

expect-webdriverio/README.md

Lines 40 to 58 in dc1f48d

	```js
	const { remote } = require('webdriverio');
	require('expect-webdriverio')
	;(async () => {
	const browser = await remote({
	capabilities: {
	browserName: 'chrome'
	}
	})
	await browser.url('https://webdriver.io')
	const $button = await browser.$('button')
	await expect($button).toBeDisplayed()
	await browser.deleteSession()
	})().catch(console.error)
	```

Some more context, in our projects people are sometimes forgetting to await Promises, this typings change together with the eslint rule no-floating-promises will allow us to highlight these bugs earlier in the development process.

For more context, see the back and forth comments starting here

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: abdel-ships-it / name: Abdel (e4f70c7)

[christian-bromann]

It seems like the tests are failing and it seems it is related to this change.

[abdel-ships-it]

@christian-bromann Im having a look 👍🏼

[abdel-ships-it]

@christian-bromann I think I found a more elegant solution that does not affect jasmine. I will rebase for clean git history, I see the tests passing as well.

[abdel-ships-it]

It seems like the tests are failing and it seems it is related to this change.

The PR is ready for review now 👌

[christian-bromann]

LGTM 👍

[christian-bromann]

Released as 3.7.0

[abdel-ships-it]

@christian-bromann I want to point out a slight problem with the v3 branch, Im seeing toBeVisible and toBeVisibleInViewport are missing in the typings, although they are supported matchers in WDIO v7 (see docs)

I believe toBeDisplayed and toBeDisplayedInViewport are identical methods so I will be using those for now

[abdel-ships-it]

Im going to add that my changes introduce unwanted side effects :/ It looks like non WDIO matchers also get the Promise return signature because of typescript global declaration merging. I will be creating a revert PR and fixing this locally using patch-package instead.