More robust approach: pickle if it exists, return plain if not

Remove previous test fix for dace parsing

src/gt4py/cartesian/gtc/dace/nodes.py

@@ -55,11 +55,12 @@ def from_json(cls, d, sdfg=None):
         # wrong format (non pickle).
         # Best mitigation is to give back the object plain if it does
         # not contain any pickling information
-        if isinstance(d, dict) and "pickle" not in d.keys():
+        if isinstance(d, dict) and "pickle" in d.keys():
+            b64string = d["pickle"]
+            byte_repr = base64.b64decode(b64string)
+            return pickle.loads(byte_repr)
+        else:
             return d
-        b64string = d["pickle"]
-        byte_repr = base64.b64decode(b64string)
-        return pickle.loads(byte_repr)
 
 
 class PickledDataclassProperty(PickledProperty, dace.properties.DataclassProperty):

tests/cartesian_tests/integration_tests/multi_feature_tests/test_dace_parsing.py

@@ -46,8 +46,6 @@ def dace_env():
         dace.config.Config.set("compiler", "cpu", "args", value="")
         dace.config.Config.set("compiler", "allow_view_arguments", value=True)
         dace.config.Config.set("default_build_folder", value=str(gt_cache_path))
-        # Need to serialize `StencilComputation` library nodes because they contain OIR for `VerticalLoop`
-        dace.config.Config.set("testing", "serialize_all_fields", value=True)
         yield