Use optional chaining on machineSelectorConfig

Signed-off-by: Phillip Rak <[email protected]>

shell/models/provisioning.cattle.io.cluster.js

@@ -886,7 +886,7 @@ export default class ProvCluster extends SteveModel {
     // The one we want is the first one with no selector.
     // If there are multiple with no selector, that will fall under the unsupported message below.
     return this.spec.rkeConfig?.machineSelectorConfig
-      .find((x) => !x.machineLabelSelector)?.config || { };
+      ?.find((x) => !x.machineLabelSelector)?.config || { };
   }
 
   get cloudProvider() {