Missed those in 967e6071

* Remove unneeded rule suppression
* Format tests/unit/.eslintrc.json
* build/.eslintrc.json: add strict for consistency

It's supported by all of our supported browsers.

Add aria-role presentation on li element when ul element has role tablist and remove dropdown from visual tests as they've been removed from doc

fix: ensure `totype` always returns stringified null/undefined when null/undefined is passed (#30383)

The `prev()` function doesn't take nodes other than elements into account. Also we could simplify things a lot using the `previousElementSibling` property. This property isn't fully supported in IE, it only works for elements, but since the `element` variable is an element, we can safely use it here.

I've also added an additional test.

I don't think we had this issue in v4, since we relied on jQuery back then.

Ref. https://developer.mozilla.org/en-US/docs/Web/API/NonDocumentTypeChildNode/nextElementSibling

"without instantiate it" should be "without instantiating it"

* Close modal with keyboard=true & backdrop=static

swap jQuery's `trigger(...)` with the more verbose native `dispatchEvent(...)`, as the former may not always behave/bubble correctly (observed while trying to write unit tests for keyboard handling of ARIA tab navigation), which may lead to this test passing even though it fails in real usage.