Create empty state for CI usage chart

🧩 Background

In #246844 (closed) we delivered VI usage charts to enable users to analyze historical usage by monthly and by project. Currently, we do not have an empty and loading state for the charts.

✨ Proposal

Design:

1. An empty state for the CI usage chart for when no information is available

Follow-up for later:

1. Design a loading state to boost perceived performance while the information is being fetch to show on the chart