Scheduled Updates: Pluralize sites in error message

[obenland]

Proposed Changes

• Adds a plural case for when scheduled updates encountered an error on one site.

Testing Instructions

• Create a schedule and downgrade a plugin.
• Run the schedule with a failure.
• Make sure it shows the correct string when viewing the scheduled updates list.

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 we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-53e0bd9868ec4fc67a8baa7ba197ad7bb8291272

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-53e0bd9868ec4fc67a8baa7ba197ad7bb8291272&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-53e0bd9868ec4fc67a8baa7ba197ad7bb8291272&env=a8c-for-agencies

[matticbot]

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

Sections (~7 bytes added 📈 [gzipped])

name                             parsed_size           gzip_size
plugins                                +28 B  (+0.0%)       +7 B  (+0.0%)
jetpack-cloud-plugin-management        +28 B  (+0.0%)       +7 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.

[TimBroddin]

🚀