Resolve "Technology Partner URLs missing from sitemap.xml"

Step 1: What is changing in this MR?

• Removes /partner routes in sitemap exclusion to avoid also excluding /partners/technology-partners

Production	Review app
https://about.gitlab.com/buyer-experience/sitemap.xml	https://3691-technology-partner-urls-missing-from-sitemap-xml.about.gitlab-review.app/buyer-experience/sitemap.xml

Step 2: Ensure that your changes comply with the following, where applicable:

• I, the Assignee, have run Axe tools on any updated pages, and fixed the relevant accessibility issues.
• These changes work on both Safari, Chrome, and Firefox.
• These changes have been reviewed for Visual Quality Assurance and Functional Quality Assurance on Mobile, Desktop, and Tablet.
• These changes work with our Google Analytics and SEO tools.
• These changes have been documented as expected.

Build Variables:

• Use Contentful Preview API

Related to #3691 (closed)