backwards compatible recursive check for None (2)

Co-authored-by: Julia Signell <jsignell@gmail.com>

Author: mishaschwartz

pystac_client/client.py

@@ -472,7 +472,9 @@ def get_items(self, *ids: str, recursive: bool = True) -> Iterator["Item_Type"]:
             yield from search.items()
         else:
             self._warn_about_fallback("ITEM_SEARCH")
-            for item in super().get_items(*ids, recursive=recursive):
+            for item in super().get_items(
+                *ids, recursive=recursive is None or recursive
+            ):
                 call_modifier(self.modifier, item)
                 yield item