Revert "Ensure that the counter for unique ids is only ever advanced once"

This reverts commit 68a81a1e4e.

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

@@ -36,10 +36,7 @@ public class BoundingBoxMapWithAIDownloader extends BoundingBoxDownloader {
 
     @Override
     protected DataSet parseDataSet(InputStream source, ProgressMonitor progressMonitor) throws IllegalDataException {
-        DataSet ds;
-        synchronized (BoundingBoxMapWithAIDownloader.class) {
-            ds = OsmReaderCustom.parseDataSet(source, progressMonitor, true);
-        }
+        DataSet ds = OsmReaderCustom.parseDataSet(source, progressMonitor, true);
         GetDataRunnable.addMapWithAISourceTag(ds, MapWithAIPreferenceHelper.getMapWithAIUrl().stream()
                 .filter(map -> map.getOrDefault("url", "no-url").equals(url))
                 .map(map -> map.getOrDefault("source", MapWithAIPlugin.NAME)).findFirst().orElse(MapWithAIPlugin.NAME));