MSD: refactor interim omnibar: extract store and events

[fushar]

Proposed Changes

• Renames click-handlers.ts to omnibar-events.ts
  • Reason: the events contain more things than just click handlers. For example:
    • notificationsAnchor (Dashboard: Anchor notifications popover when toggled via 'n' shortcut #109826)
    • notificationsUnseenCount (MSD: wire up unseen notification dot icon logic in interim omnibar #109858)
• Extracts createOmnibarStore from interim-omnibar.tsx‎ into omnibar-store.ts
  • Reason: I will be adding more things to the store:
    • NOTIFICATIONS_UNSEEN_COUNT_SET action (MSD: wire up unseen notification dot icon logic in interim omnibar #109858)
    • a future PR where we store the "current site"
  • Also to extract .ts logic from .tsx, and to make it symmetrical to omnibar-events.ts above.

Why are these changes being made?

Making me less dizzy.

Testing Instructions

Verify no regressions.

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-175211

Jetpack Cloud Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-175211&env=jetpack

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https://calypso.live?image=registry.a8c.com/calypso/app:build-175211&env=a8c-for-agencies

Dashboard Live (dotcom) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-175211&env=dashboard

Dashboard Live (CIAB) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-175211&env=dashboard-ciab

[matticbot]

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

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

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

To test WordPress.com changes, run install-plugin.sh $pluginSlug omnibar-refactor on your sandbox.

[p-jackson]

Yes! This has grown into a lot more than just "click handlers" 😄

Thanks for the tidy up.