fix(the source): encode social share links

Closes #3969 (closed)

Changes in MR

• Adds URL encoding to title and URL strings to create proper social share links

Testing

Production:

https://about.gitlab.com/the-source/security/security-its-more-than-culture-addressing-the-root-cause-of-common-security/

Ex: X/Twitter link 404s

Review App:

https://3969-the-source-article-template-twitter-link-broken.about.gitlab-review.app/the-source/security/security-its-more-than-culture-addressing-the-root-cause-of-common-security/

Ex: X/Twitter link works