refactor(job): Extract mount options validation to helper function

Author: Neelabh94

cmd/job/submit.go

@@ -125,12 +125,8 @@ and JobSet/Kueue specific configurations like workload name, queue, nodes, and r
 
 		priorityClassName = strings.ToLower(priorityClassName)
 
-		if mountOptions != "" {
-			for _, m := range volumeStr {
-				if !strings.HasPrefix(m, "gs://") {
-					return fmt.Errorf("--mount-options is currently only supported for GCS fuse volumes (gs://...)")
-				}
-			}
+		if err := validateMountOptions(); err != nil {
+			return err
 		}
 
 		return nil
@@ -390,6 +386,17 @@ func validateGKENAPFlags() error {
 	return nil
 }
 
+func validateMountOptions() error {
+	if mountOptions != "" {
+		for _, m := range volumeStr {
+			if !strings.HasPrefix(m, "gs://") {
+				return fmt.Errorf("--mount-options is currently only supported for GCS fuse volumes (gs://...)")
+			}
+		}
+	}
+	return nil
+}
+
 func ensureDryRunDir(path string) error {
 	if len(path) > 0 && os.IsPathSeparator(path[len(path)-1]) {
 		return fmt.Errorf("the dry-run-out path %q must be a file path, not a directory path", path)