Revise text and fix link color in cookie consent banner

[josh-wong]

Description

This PR:

• Clarifies the wording in the cookie consent banner.
• Fixes an issue where the hyperlinked text to the cookie policy in the cookie consent banner is impossible to see when the site is using the light theme.

Related issues and/or PRs

• Add cookie consent banner #155

Changes made

• Revised the text in the cookie consent banner for clarity.
• Hard-coded a style for the cookie consent banner to make the hyperlinked text appear when the site is using the light theme.

Checklist

The following is a best-effort checklist. If any items in this checklist aren't applicable to this PR, add N/A after each item.

Documentation

• I have updated the side navigation as necessary. N/A
• I have updated the documentation to reflect the changes. N/A
• I have documented or updated any remaining open issues linked to this PR in GitHub, Obsidian, etc. N/A

Build, deploy, and test

• I have merged and published any dependent changes in other PRs. N/A
• I have commented my code, particularly in hard-to-understand areas. N/A
• I have checked that my changes look as expected on a locally built version of the docs site.
• My changes generate no new warnings.

[github-actions]

All items in the checklist have been checked🎉