Fixed ESM issue with validator-ajv8

[heath-freenome]

Reasons for making this change

There is another place where the ESM build needs an update to for proper import of AJV standalone code.

• Added a new ajvReplacer that adds /index.js to the end of ajv/dist/standalone
• Updated @rjsf/validator-ajv8 to add the ajvReplacer to the tsconfig.replacer.json and tsc.build.json
  • Also fixed up some formatting around imports in a few files
• Updated .gitignore to add ajvReplacer.js
• Updated formTests.ts to add tests for the fix in #4519
  • Updated the snapshots for these new tests
• Updated the CHANGELOG.md accordingly

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