fix: use null as a notSetValue for examplesForMediaType

fixes #5455

Author: shockey

src/core/plugins/oas3/components/request-body.jsx

@@ -67,7 +67,7 @@ const RequestBody = ({
 
   const mediaTypeValue = requestBodyContent.get(contentType, OrderedMap())
   const schemaForMediaType = mediaTypeValue.get("schema", OrderedMap())
-  const examplesForMediaType = mediaTypeValue.get("examples", OrderedMap())
+  const examplesForMediaType = mediaTypeValue.get("examples", null)
 
   const handleExamplesSelect = (key /*, { isSyntheticChange } */) => {
     updateActiveExamplesKey(key)