docs: fix changelog links and remove versions without corresponding changelogs (#52849)

Summary:
- The  changelog docs has broken links for the pre v0.80 markdowns due to missing extension
- There are links without corresponding changelogs

## Changelog:

<!-- Help reviewers and the release process by writing your own changelog entry.

Pick one each for the category and type tags:

For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests
-->

[INTERNAL] [FIXED] - fix changelog links and remove versions without corresponding changelogs

Pull Request resolved: https://github.com/facebook/react-native/pull/52849

Test Plan: Click on each link to see if it opens the corresponding page at the specific section

Reviewed By: christophpurrer, cortinico

Differential Revision: D79097825

Pulled By: cipolleschi

fbshipit-source-id: a92e709ccbb45a042175bd198326132bfbf37c65