Update/change go back behavior in my jetpack

[jboland88]

Proposed changes:

• This PR changes the behavior of the "Go back" button on My Jetpack product interstitial pages to always return to the My Jetpack homepage
• Previously, it would just go back in history, which produced some odd edge cases

Testing instructions:

• Load up My Jetpack on a test site with this PR
• Click "Learn more" on the backup, card - this takes you to: /wp-admin/admin.php?page=my-jetpack#/add-backup
• Now, manually change the URL to /wp-admin/admin.php?page=my-jetpack#/add-protect in the address bar and press enter.
• From the protect interstitial, click "go back" in the upper left
• This should send you back to the main My Jetpack page

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the update/change-go-back-behavior-in-my-jetpack branch.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack update/change-go-back-behavior-in-my-jetpack
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

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[IanRamosC]

LGTM! But you need a rebase/merge before merging the PR