Remove same day countdown zero

[robhuzzey]

What does this PR do? (please provide any background)

Makes countdown clock end at zero & takes a time into account. (removes the feature of displaying zero on the same day regardless of time passed in).

What tests does this PR have?

I have added a couple of additional tests for the functionality I have included

How can this be tested?

I would run the docs as per the readme & then see the countdown clock behaving as expected (pass in a todays date & time + 3o seconds & watch it stop on zero).

Screenshots / Screencast

N/A

What gif best describes how you feel about this work?

---

• [x] I have checked our general contributing document and the project specific contributing document (if present) and I'm happy for this to be reviewed.

  Reviewers

Review 1

• [x] :+1:

Review 2 *

• [x] :+1:

Review 3 (optional)

• [ ] :+1:

By adding a +1 you are confirming you have...

• Witnessed the work behaving as expected (this could be on the author's machine or screencast).
• Checked for coding anti-patterns.
• Checked for appropriate test coverage.
• Checked all the tests are passing.

* for HX this review must be completed by an SE, SA or Project Guru

[hxpaul]

taking a :two: - looks a sensible change to me, a good fix. I am not close to where this is used, needs someone who's using this (in heha maybe?) to say if it will cause a problem. It being versioned should sort that out though.

[elliottcrush]

Works great for me, good change. :one: :+1:

[robhuzzey]

@hxpaul when you get a sec. I've updated based on your PR feedback & would love a +1 if you're happy. Thanks.

[hxpaul]

Looks good to me 👍