feat(PPDSC-2226): functionality to dismiss popover

[tbradbury]

PPDSC-2226

What

1. Background - why this is needed - Requested functionality for Audio Player requires change to Popover so when you click outside of popover or press esc the popover closes.
2. What did you do - Added a new prop called enableDismiss that when set to true enables the above functionality. Original idea was to have to props so that clicking outside Popover or using esc key could be enables separately. However we are using the floating-ui library where this functionality comes as a package.
3. What should the reviewers expect - When enableDismiss set to true you can click outside of popover or press esc and popover will close

I have done:

• Written unit tests against changes
• Written functional tests against the component and/or NewsKit site
• Updated relevant documentation

I have tested manually:

• The feature's functionality is working as expected on Chrome, Firefox, Safari and Edge
• The screen reader reads and flows through the elements as expected.
• There are no new errors in the browser console coming from this PR.
• When visual test is not added, it renders correctly on different browsers and mobile viewports (Safari, Firefox, small mobile viewport, tablet)
• The Playground feature is working as expected

Before:

After:

Who should review this PR:

How to test:

[newskit-engineering]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2226-popover
Storybook: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2226-popover/storybook