Align code with polygon-only training

configs/marine_feature_multitask.json

@@ -47,9 +47,9 @@
         "type": "instance_segmentation",
         "enabled_when": "element card includes instance_segmentation"
       },
-      "object_detection": {
-        "type": "detection",
-        "enabled_when": "element card includes detection"
+      "polygon_element": {
+        "type": "sampoly_style_polygon_extraction",
+        "enabled_when": "element card includes polygon_extraction"
       },
       "anomaly_or_change": {
         "type": "optional",