Patterns Modals: Close dialog label creates scrollbar

[ryelle]

When hovering over the X on either the "How to use patterns…" or report modals, the tooltip that says close dialog creates a horizontal scrollbar.

https://user-images.githubusercontent.com/541093/120674775-7002c180-c462-11eb-97b4-4c1fe6912916.mov

This is Mac/Firefox. The flash in the video doesn't happen on wp.org/patterns, so that might just be a local issue.