BackupScheduleSetting: improve BackupScheduled view using useNextBackupSchedule hook

[Initsogar]

Related to https://github.com/Automattic/jetpack-backup-team/issues/715

This PR improves the precision of the next backup time estimation by leveraging the useNextBackupSchedule hook introduced in #95602 that returns the next scheduled backup date.

Proposed Changes

• Removed the previous logic that calculated hours until the next backup using the last backup date and replaced it with precise scheduling data from the useNextBackupSchedule hook.
  • If there are any minutes left in the calculation, the hours are rounded up to the next hour.

Other minor changes:

• Removed defaultProps on ActionsButton component, which is now deprecated. Update: I was going to remove this, but it seems we have some types issues related to this, so I prefer to address it in a new PR.
• Refactor useNextBackupSchedule to named export instead of default export, so we could add more hooks in the same hooks file without issues.
• Update schedule backup message in settings page as suggested in p1729507641013709-slack-C07LJAE7AVD

Scenario	Before	After
Time set by default
Time set by user

Why are these changes being made?

The previous logic considered the last completed backup to calculate a relative date, which is not always accurate, especially since we introduced on-demand backups.

https://github.com/Automattic/jetpack-backup-team/issues/715

Testing Instructions

• Spin up a Jetpack Cloud live branch.
• Pick a site with Jetpack VaultPress Backup plan with no backups today.
• Navigate to the Backup page.
• You should see the Backup Scheduled view and the time should be relative to the site scheduled time.
• You can try updating the daily backup time setting and see how it affects the "In the next % hour/s" message.

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 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 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-122705

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-122705&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-122705&env=a8c-for-agencies

[matticbot]

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

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

• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug update/schedule-backups-upcoming-view on your sandbox.

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

Sections (~227 bytes added 📈 [gzipped])

name                           parsed_size           gzip_size
jetpack-cloud-agency-sites-v2       +663 B  (+0.0%)     +154 B  (+0.0%)
backup                              +663 B  (+0.1%)     +154 B  (+0.0%)
a8c-for-agencies-sites              +663 B  (+0.0%)     +154 B  (+0.0%)
jetpack-cloud-settings              +139 B  (+0.0%)      +73 B  (+0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[Initsogar]

@ilonagl here I included the changes on the changes on the scheduled setting message:

Scenario	Before	After
Time set by default
Time set by user

[Initsogar]

I was testing this on Jetpack Cloud live branch and noted this error:

It seems nextBackupDate could be potentially null, so I'd need to add some guard checks here.

[a8ci18n]

This Pull Request is now available for translation here: https://translate.wordpress.com/deliverables/16942926

Some locales (Hebrew, Japanese) have been temporarily machine-translated due to translator availability. All other translations are usually ready within a few days. Untranslated and machine-translated strings will be sent for translation next Monday and are expected to be completed by the following Friday.

Thank you @Initsogar for including a screenshot in the description! This is really helpful for our translators.