prefer-to-have-count: warn about `.toHaveLength()`

[EvgenyOrekhov]

trafficstars

It's a feature request to add one more case to prefer-to-have-count rule.

The following code should be considered invalid:

expect(await page.getByText("test").all()).toHaveLength(2);

The following code should be considered valid:

await expect(page.getByText("test")).toHaveCount(2);