fix(OAS3): servers component update on definition change (#6280)

* fix(OAS3): servers component should use nextProps

* test(OAS3): cypress tests for selecting multiple servers

* test(OAS3): multiple server test with definition change

src/core/plugins/oas3/components/servers.jsx

@@ -30,9 +30,9 @@ export default class Servers extends React.Component {
       servers,
       setServerVariableValue,
       getServerVariable
-    } = this.props
+    } = nextProps
 
-    if(this.props.currentServer !== nextProps.currentServer) {
+    if (this.props.currentServer !== nextProps.currentServer || this.props.servers !== nextProps.servers) {
       // Server has changed, we may need to set default values
       let currentServerDefinition = servers
         .find(v => v.get("url") === nextProps.currentServer)