Substack importer: reset state properly after import is finished

[simison]

Previously, state would not get reset/end up in weird state if you would right-click copy the URL from any of the summary CTAs (onClick wouldn't run), OR click anything else around calypso sidebar.

This ensures state gets reset.

Proposed Changes

• Resets the importer engine state on leaving the summary step IF the importer is finished. Otherwise should let leaving and not rest the state, and allow returning to see the state progressing.
• Removes clearing state on clicking summary CTAs.

Why are these changes being made?

Testing Instructions

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-124678

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-124678&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-124678&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/substack-importer-reset-after-summary on your sandbox.

[matticbot]

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

Sections (~3 bytes added 📈 [gzipped])

name    parsed_size           gzip_size
import        -11 B  (-0.0%)       +3 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.

[simison]

Feels like needs a bit more work.