Improvement: Add an horizontal divider at the bottom/end of Popup Controls block options

[marklchaves]

Describe the feature request

There should be a HR at the end of the Popup Controls block options panel to:

1. Be consistent with the other block options panels
2. Be clearer when the Popup Controls options end and the next block options panel begins.

See screen capture.

Use case

See above.

Example screenshots (if any)

No divider

Examples of existing dividers