#7567916 Plugin Management: show neutral state for already up-to-date plugins when clicked on update

Proposed Changes

The PR adds a neutral state to the plugin update status that shows Plugin already up to date instead of showing Update successful.

Testing Instructions

NOTE: You can test these changes in Calypso Blue or Green.

Prerequisites

Since this change is made specifically for agencies, you must set yourself(partner) as an agency if you want to test in Calypso Green – 2c49b-pb. Make sure to switch it back to the previous type.

Instructions

1. Run git checkout update/add-neutral-state-for-plugin-update and yarn start-jetpack-cloud or yarn start if you want to test these changes in Calypso Blue.
2. Open http://jetpack.cloud.localhost:3000/, and you’ll be redirected to the /dashboard -> Click on Plugins in the sidebar or visit http://calypso.localhost:3000/plugins/manage if you want to test these changes in Calypso Blue.
3. Click on Edit All -> Click on Update Plugins and verify the status for already up-to-date plugins shows Plugin already up to date

Before	After

Pre-merge Checklist

Complete applicable items on this checklist before merging into the trunk. Inapplicable items can be left unchecked.

The PR author and reviewer are responsible for completing the checklist.

• Have you written new tests for your changes?
• Have you tested the feature in Simple, Atomic, and self-hosted Jetpack sites?
• Have you checked for TypeScript, React, or other console errors?
• Are we memoizing when appropriate (for expensive computations)? More info in Our Approach to Data and Memoizing with create-selector and Using memoizing selectors
• Have we sent any new strings for translation ASAP?

Related to 1202619025189113-as-1203011720281491