The description of the selected option in the new Greeter's "Add Additional Setting" window is barely visible

When I click on the “+” button in the Additional Settings section then
the “Add Additional Setting” window opens and the topmost item (i.e.
“Administrative Account”) is selected and thus completely blue. The
description (i.e. “Perform Administrative Tasks”) has a gray font that I
find barely visible on the blue background.

Parent Task: #10828 (closed)

Original created by @segfault on 11311 (Redmine)