Domain management: Remove back button from email upsell screen when not purchasing a domain

[m1r0]

Resolves #98331

Proposed Changes

• Remove the back button from the /email/:domain/manage/:site_slug screen. This makes it consistent with /email/:domain.

Why are these changes being made?

• The back button was pointing to /email/:domain which is not helpful.

Testing Instructions

No purchase flow:

• Go to /email/:domain/manage/:site_slug and make sure there is no back button.

Purchase flow:

• Go to /domains/add/:site_slug
• Select a domain.
• In the email upsell step, ensure that both the back button and the skip button are displayed and work properly (same as before).

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-130195

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-130195&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-130195&env=a8c-for-agencies

[matticbot]

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

Sections (~11 bytes removed 📉 [gzipped])

name     parsed_size           gzip_size
hosting        -28 B  (-0.0%)      -11 B  (-0.0%)
email          -28 B  (-0.0%)      -11 B  (-0.0%)
domains        -28 B  (-0.0%)      -11 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.

[phcp]

Nice work! Changes work as described in both scenarios.