Launchpad My Home: Showing snackbar when a task was completed

[vykes-mac]

Related to #98839

Proposed Changes

• Show onboarding launchpad next step snackbar when publishing first post.

Why are these changes being made?

Testing Instructions

• Apply this branch on your local Calypso

• Make sure widgets.wp.com is sandboxed.

• Run install-plugin.sh wbe add/task-next-step-snackbar on sandbox

• Create a new post using the onboarding flag: http://calypso.localhost:3000/post/{domain}?#publish-first-post

• Inspect the page and open the iFrame URL in a new tab
  https://{siteSlug}/wp-admin/post.php?post=44&action=edit&calypsoify=1&block-editor=1&frame-nonce=ed0785d2f4&origin=http%3A%2F%2Fcalypso.localhost%3A3000&environment-id=development&support_user=&_support_token#publish-first-post

• After publishing a post, you should see a snackbar with next steps link

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 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-131060

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-131060&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-131060&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

• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug add/task-next-step-snackbar on your sandbox.

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.