fix: Don't let start service migration if the same volume was picked

lib/ui/pages/server_storage/binds_migration/services_migration.dart

@@ -55,6 +55,20 @@ class _ServicesMigrationPageState extends State<ServicesMigrationPage> {
     });
   }
 
+  bool get isTherePendingChange {
+    bool isChangeFound = false;
+    for (final Service service in widget.services) {
+      for (final String serviceId in serviceToDisk.keys) {
+        if (serviceId == service.id &&
+            serviceToDisk[serviceId] != service.storageUsage.volume!) {
+          isChangeFound = true;
+        }
+      }
+    }
+
+    return isChangeFound;
+  }
+
   /// Check the services and if a service is moved (in a serviceToDisk entry)
   /// subtract the used storage from the old volume and add it to the new volume.
   /// The old volume is the volume the service is currently on, shown in services list.
@@ -157,6 +171,8 @@ class _ServicesMigrationPageState extends State<ServicesMigrationPage> {
               ),
             ),
             const SizedBox(height: 16),
+            if (widget.isMigration ||
+                (!widget.isMigration && isTherePendingChange))
               BrandButton.filled(
                 child: Text('storage.start_migration_button'.tr()),
                 onPressed: () {