[xml/en] Update xml schema further learning resource link

[Maheshkumar-novice]

• [x] I solemnly swear that this is all original content of which I am the original author
• [x] Pull request title is prepended with [language/lang-code] (example [python/fr-fr] or [java/en])
• [x] Pull request touches only one file (or a set of logically related files with similar changes made)
• [ ] Content changes are aimed at intermediate to experienced programmers (this is a poor format for explaining fundamental programming concepts)
• [ ] If you've changed any part of the YAML Frontmatter, make sure it is formatted according to CONTRIBUTING.md
  • [] Yes, I have double-checked quotes and field names!

[Maheshkumar-novice]

These changes are applied because the current resource link is 404. I have another doubt is there any reason why we are using http for links instead of https? It redirects to https anyway but just curious.

[verhovsky]

#4746