Changing link colors to be higher contrast

Increasing Access

This issue addresses link color accessibility, specifically changing the link color so it meets W3CAG guidelines on color contrast requirements for small text.

Feature enhancement details

see #4031 for discussion and context.

General:
In client/styles/abstracts/_variables.scss

• rename #ffa9d9 (currently p5-contrast-pink) to p5-contrast-light-pink
• create a variable called p5-contrast-dark-pink for the color #b20046
• update any prior references to p5-contrast-pink to use p5-contrast-light-pink instead

Dark mode: change all links to p5-contrast-light-pink (#ffa9d9)

Light mode: change all links to p5-contrast-dark-pink (#b20046)

The links could be changed one by one or by creating a link-text-color variable in each theme and making the links reference their theme's color.

PR Criteria:

• Provide screenshots in your PR of the visual changes implemented
• Provide quality assurance steps for how reviewers can ensure your changes are made properly
• use variable names for component colors (eg p5-contrast-light-pink, not the hex code #ffa9d9)