Improve UI text of group settings Insights area

What does this MR do and why?

• Improves styling of the Insights subtitle in the group settings page. The text is currently set to a non-standard style. This MR corrects the style to comply with the standard.
• Changes "Learn more" link text to something more useful and standards compliant.

Part of #350107 (closed).

Screenshots or screen recordings

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Navigate to a group.
2. In the sidebar, select Settings > General.
3. Expand the Insights section.

• View the Insights section's subtitle
• View the label, particularly its color.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.