fix(#3553):Broken Link for Custom Widgets and Fields in UISchema Page

[Sachin-chaurasiya]

Reasons for making this change

I worked on updating the broken link in the documentation.
Fixes #3553

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Checklist

• I'm updating documentation
  • I've checked the rendering of the Markdown text I've added
• I'm adding or updating code
  • I've added and/or updated tests. I've run npm run test:update to update snapshots, if needed.
  • I've updated docs if needed
  • I've updated the changelog with a description of the PR
• I'm adding a new feature
  • I've updated the playground with an example use of the feature

[heath-freenome]

@Sachin-chaurasiya Closing in favor of #3574. Thanks for finding the issue and it took us a while to understand how things got broken. Now we have the better fix ready