Make fields with const pre-fiiled and readonly #3843

[abdalla-rko]

Reasons for making this change

Continued the work from #3843. Fixes #2600.

If fields have const definition, make the value as pre-filled default and also make the fields readonly. (current logic will just ignore the const value and leave blank input for users.

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 npx nx run-many --target=build --exclude=@rjsf/docs && 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