Add a button to reset example when user modifys request body

[russbot]

Description

Added a button to RequestBodyEditor to reset to the example once the user has edited the request body.

Motivation and Context

Once you edit the request body, or completely delete it, there is no way to get the example data back other than refreshing the page.

How Has This Been Tested?

I built the project and loaded an OAS3 file to test modifying the body of a post.
Only minimal additions were necessary.

Screenshots (if appropriate):

https://imgur.com/a/edJIl

Checklist

My PR contains...

• No code changes (src/ is unmodified: changes to documentation, CI, metadata, etc.)
• Dependency changes (any modification to dependencies in package.json)
• Bug fixes (non-breaking change which fixes an issue)
• Improvements (misc. changes to existing features)
• Features (non-breaking change which adds functionality)

My changes...

• are breaking changes to a public API (config options, System API, major UI change, etc).
• are breaking changes to a private API (Redux, component props, utility functions, etc.).
• are breaking changes to a developer API (npm script behavior changes, new dev system dependencies, etc).
• are not breaking changes.

Documentation

• My changes do not require a change to the project documentation.
• My changes require a change to the project documentation.
• If yes to above: I have updated the documentation accordingly.

Automated tests

• My changes can not or do not need to be tested.
• My changes can and should be tested by unit and/or integration tests.
• If yes to above: I have added tests to cover my changes.
• If yes to above: I have taken care to cover edge cases in my tests.
• All new and existing tests passed.

[shockey]

Hey @russbot! Thanks for this.

Can you revert the changes to dist/?

[russbot]

@shockey done! thanks! let me know if you need me to make any other changes.