Popup fix: Property 'transitionEnd' is never assigned, so banner doesn't set display to 'none' after it fades + broken unit test

[ryco404]

The transitionEnd property is never assigned when checking the compatibie transition class meaning that the correct transitionEnd event is never listened to, meaning that display: none never gets set after the popup fades, so the popup window, in the case of revocable popups, when faded will still occlude elements on the page.

Also fixed broken unit test, the 'updates content options link and messagelink' test fails when running Jest, this is due to the regionalLaw property being missing on the passed in options, but also missed on the default object, meaning that it never gets merged, so the property will always be undefined - even when set on the options object.