fix: Sponsor and About Working Groups nav links

Adds proper url

requested review from @cguindon

Deploy Preview for www.eclipse.org is ready [ 2 min 49 sec]

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Test locally docker run -it --rm -p 18181:8080 docker.io/eclipsefdn/www-eclipse-org:mr-103--7636b5a-b1 and open to http://localhost:18181

Browse the preview: https://preview-103--www-eclipse-org.eclipsecontent.org/

approved this merge request

mentioned in commit f3ce8532

merged