Ensure that a List is serializable

Signed-off-by: Taylor Smock <taylor.smock@kaart.com>

src/main/java/org/openstreetmap/josm/plugins/mapwithai/backend/MapWithAIDataUtils.java

@@ -66,7 +66,7 @@ public final class MapWithAIDataUtils {
 
         public GetDataRunnable(List<BBox> bbox, DataSet dataSet, PleaseWaitProgressMonitor monitor) {
             super();
-            this.bbox = bbox;
+            this.bbox = new ArrayList<>(bbox);
             this.dataSet = dataSet;
             this.monitor = monitor;
         }