My Home: Add new stats card for experimental layout #3419941

Changes proposed in this Pull Request

Adds a new version of the “Stats at a glance” card to the experimental home layout.

Site	Desktop	Mobile
Unlaunched
Site with no traffic
Site with traffic

Testing instructions

• Load the experimental home layout: /home/:site/?flags=home/experimental-layout for an unlaunched site.
• Make sure the stats card is displayed with a placeholder that sets expectations for this section.
• Make sure the “Learn about stats” link opens the stats support doc in a dialog.
• Switch to a launched site with traffic.
• Make sure the stats cards displays a chart with the traffic of the last week (last 7 days).
• Make sure the most popular day and time of the previous 7 days is displayed below the chart.
• Make sure the card displays the title the most visited post during the previous 7 days.
• Make sure the card displays the title the most visited page during the previous 7 days.
• Make sure the total views of the last week are displayed if no posts OR pages were visited during the previous 7 days.
• Make sure the total visitors of the last week are displayed if no posts AND pages were visited during the previous 7 days.
• Switch to a launched site without traffic.
• Make sure the stats card is displayed with a placeholder that includes a snippet educating users about stats.
• Make sure the “Read more” link opens the stats support doc in a dialog.

Fixes #41034