Improve formatDate, add more unit tests

[waitingallday]

Issue:

What I did

• Fixes formatDate doesn't allow Intl.DateTimeFormat options #947

How to test

• Added unit tests for formatDate and distanceAsPercentage

Checklist

For all PR's

• I've added relevant changes to the project Readme if needed
• I've updated the documentation site as needed
• I have added tests to cover my changes (if not applicable, please state why in a comment)

For new UI components only

• I have added a storybook story covering all variants
• I have checked a11y tab in storybook passes
• I have added cypress component tests (if the component is interactive)
• Any events are emitted on the event bus using emitRplEvent

[cypress]

ripple-framework    Run #2375

Run Properties:   Passed #2375  •  326c23c071: fix(@dpc-sdp/ripple-ui-core): :bug: improve formatDate, add more unit tests

Project	ripple-framework
Branch Review	fix/format-date-options
Run status	Passed #2375
Run duration	09m 16s
Commit	326c23c071: fix(@dpc-sdp/ripple-ui-core): :bug: improve formatDate, add more unit tests
Committer	Jason Smith
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Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	211
View all changes introduced in this branch ↗︎