Improve enum values for Enum Type in Swagger ReadOnly documentation (#4191)

* Adding enum values for Enum Type in Swagger ReadOnly documentation

* Adding enum values for Enum Type in Swagger ReadOnly documentation (optimisation) and also adding default/example value

* Add new display enums, defaults, and examples when not in TIO mode (another way to have enums values in swagger.json)

* Fix npm test result

* review corrections

* fix: don't render parameter description if field is empty

* use cross-version schema variable to access properties

* pass className through Markdown component usage

* add per-field classNames to Markdown for easier styling + testing

* remove parameter Example field (out-of-scope for this PR)

* get default value from schema instead of top-level parameter

* tests: add e2e cases for swagger2 and oas3

* remove `swagger-petstore-enum.json`

the purpose of this file lives on in the e2e test specs folder

* add missing proptypes validation

* use `classnames` to more effectively union class names

src/core/plugins/oas3/wrap-components/markdown.js

@@ -1,11 +1,12 @@
 import React from "react"
 import PropTypes from "prop-types"
 import ReactMarkdown from "react-markdown"
+import cx from "classnames"
 import { Parser, HtmlRenderer } from "commonmark"
 import { OAS3ComponentWrapFactory } from "../helpers"
 import { sanitizer } from "core/components/providers/markdown"
 
-export const Markdown = ({ source }) => { 
+export const Markdown = ({ source, className = "" }) => {
   if ( source ) {
     const parser = new Parser()
     const writer = new HtmlRenderer()
@@ -19,14 +20,15 @@ export const Markdown = ({ source }) => {
     return (
       <ReactMarkdown
         source={sanitized}
-        className={"renderedMarkdown"}
+        className={cx(className, "renderedMarkdown")}
       />
     )
   }
   return null
 }
 Markdown.propTypes = {
-  source: PropTypes.string
+  source: PropTypes.string,
+  className: PropTypes.string,
 }
 
-export default OAS3ComponentWrapFactory(Markdown)
+export default OAS3ComponentWrapFactory(Markdown)