Fix 4782 to support proper live validation

[heath-freenome]

Reasons for making this change

Fixed #4782 by fixing getStateFromProps() around the new skipLiveValidate optimization flag
Fixed #4783 by fixing Form to merge errors while filtering when customValidate is provided
Fixed #4784 by fixing Form to allow non-empty leaf level objects when omitExtraData is active

• Updated Form to skip clearing the errorSchema for a field that was changed when the mustValidate flag is true
  • Updated the mustValidate flag to remove the !skipLiveValidate from it's assignment, moving it to the live validation branch instead
  • Updated filterErrorsBasedOnSchema() to properly merge errors when customValidate is provided
  • Updated getFieldNames() to allow returning non-empty objects for leaf-level fields
• Updated Playground to make the onChange() handler separate the event from the destructure to assist in better debugging
• Updated the CHANGELOG.md file 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