Add to heartbeat API to keep useConnection composable more tightly encapsulated in the heartbeat module.

[rtibbles]

Summary

• Adds to the heartbeat API so it can be imported and used, rather than committing to exposing the useConnection composable more broadly.

References

In support of #5488

Reviewer guidance

If you turn the network to 'offline' in the network tab, does the disconnection overlay still properly register the reconnection time?

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Testing checklist

• [ ] Contributor has fully tested the PR manually
• [ ] If there are any front-end changes, before/after screenshots are included
• [ ] Critical user journeys are covered by Gherkin stories
• [ ] Critical and brittle code paths are covered by unit tests

PR process

• [ ] PR has the correct target branch and milestone
• [ ] PR has 'needs review' or 'work-in-progress' label
• [ ] If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• [ ] If this is an important user-facing change, PR or related issue has a 'changelog' label
• [ ] If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

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Build Artifacts

Asset type	Download link
PEX file	kolibri-0.18.0.dev0_git.20241003144945.pex
Windows Installer (EXE)	kolibri-0.18.0.dev0+git.20241003144945-windows-setup-unsigned.exe
Debian Package	kolibri_0.18.0.dev0+git.20241003144945-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.18.0.dev0+git.20241003144945.dmg
Android Package (APK)	kolibri-0.18.0.dev0+git.20241003144945-0.1.4-debug.apk
TAR file	kolibri-0.18.0.dev0+git.20241003144945.tar.gz
WHL file	kolibri-0.18.0.dev0+git.20241003144945-py2.py3-none-any.whl