feat(PPDSC-2182): added initialTime prop and test

[agagotowiec]

PPDSC-1961

What

Added initialTime prop to the audio-player-composable to allow customers to start the audio from a specific time.
Added a new scenario in the storybook with initial props both for time and volume.

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

After:

How to test:
Please check the audio-player-with-initial-props scenario in the storybook

[newskit-engineering]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-1961-initial-start-point-audioplayer
Storybook: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-1961-initial-start-point-audioplayer/storybook

[Srinivasan-Ramasamy]

Looks good 👍

[mutebg]

Well done @agagotowiec