properly load workspace cluster store outside of render() (#2320)

also minor bulletproofing for cluster version string

Signed-off-by: Jim Ehrismann <jehrismann@mirantis.com>

src/main/cluster.ts

@@ -252,7 +252,7 @@ export class Cluster implements ClusterModel, ClusterState {
    * Kubernetes version
    */
   get version(): string {
-    return String(this.metadata?.version || "");
+    return String(this.metadata?.version ?? "");
   }
 
   constructor(model: ClusterModel) {