#5513308 Jetpack Plans: Make multisite incompatible products disabled.

Changes proposed in this Pull Request

This PR makes multisite incompatible products and plans disabled (and translucent) with a message “Not available for multisite WordPress installs”

Multisite incompatible products are all Jetpack Backup and Jetpack Scan products and all plans which include Backup and/or Scan products.

Fixes: 1164141197617539-as-1199895424508971

Testing instructions

• Checkout and run this PR in both Calypso blue and green concurrently.
• Select a multisite connected site (or create a multisite JN site if you don’t already have one in your account)
• Go to the Calypso blue Plans page: calypso.localhost:3000/plans/:site
• Verify that all Jetpack products/plans (other than Anti-Spam, Site Search, and CRM Entrepreneur) are disabled (and translucent) and display the message, “Not available for multisite WordPress installs”. (See screenshot below)
• Go to Calypso green Plans page jetpack.localhost:3001/pricing/:site and verify the same as above.
• Select a non-multisite site and verify the plans/products are not disabled.

Calypso blue, showing disabled multisite products

Calypso green showing disabled multisite products