Remove broken links to grafana.fun servers, add link to test-api.k6.io.
Checklist
[x] I have used a meaningful title for the PR.
[x] I have described the changes I've made in the "What?" section above.
[x] I have performed a self-review of my changes.
[x] I have run the npm start command locally and verified that the changes look good.
[x] I have made my changes in the docs/sources/next folder of the documentation.
[x] I have reflected my changes in the docs/sources/v{most_recent_release} folder of the documentation.
[ ] I have reflected my changes in the relevant folders of the two previous k6 versions of the documentation (if still applicable to previous versions).
What?
Remove broken links to grafana.fun servers, add link to test-api.k6.io.
Checklist
npm startcommand locally and verified that the changes look good.docs/sources/nextfolder of the documentation.docs/sources/v{most_recent_release}folder of the documentation.Related PR(s)/Issue(s)