Backups: show dates in the site timezone

[myhro]

Part of DOTDASH-543.

This PR is related to #105954, but doesn't depend on it.

Proposed Changes

• Add timezone support to the useFormattedTime hook.
• Make use of timezones on all backup pages.

Why are these changes being made?

When the DateRangePicker component is fixed, we'll use the site timezone to filter dates. We need to display them in the same timezone to avoid inconsistencies, like an entry being displayed the day before/after the filtering.

This is also in line with the way Jetpack Cloud handles timezones:

Testing Instructions

• Go to /v2/sites/:slug/backups
• Check the dates for backup list, details and download/restore pages.
• Confirm they match the dates in Jetpack Cloud.

Before	After

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-157406

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-157406&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-157406&env=a8c-for-agencies

[Initsogar]

I ran some tests, and it works as expected 👍🏽

Since this affects the useFormattedTime hook, I’d love to hear @Automattic/lego’s thoughts as well.

[fushar]

Since this affects the useFormattedTime hook, I’d love to hear @Automattic/lego’s thoughts as well.

I think it will be beneficial for everyone to add tests to the useFormattedTime() hook. I got lost reading the changes 😂

[myhro]

I think it will be beneficial for everyone to add tests to the useFormattedTime() hook. I got lost reading the changes 😂

Tests were added and can be run with:

 $ yarn test-client client/dashboard/components/formatted-time/test/index.tsx

Can you please check again?

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• help-center
• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug add/backups-site-timezone on your sandbox.

[myhro]

@fushar Hi. This is a gentle ping in case you missed the last week one. Can you please review this PR?

[fushar]

Thanks for the ping. Tests are nice. Thanks!