Skip default fallback logic when cls is specified

`cls` will provide its own default serialization mechanism, passing a `cls`
Encoder class is now also a way to opt-out of our patching shenanigans and just
use your own code.

This will work, provided the library doing the JSON encoding isn't also using
their own custom class.

reflex/state.py

@@ -3729,6 +3729,7 @@ def _json_dumps_wrapper(*args, **kwargs):
     Returns:
         The JSON string.
     """
+    if "cls" not in kwargs:
         _orig_default = kwargs.pop("default", None)
 
     def _default(obj):
@@ -3743,6 +3744,7 @@ def _json_dumps_wrapper(*args, **kwargs):
             pass
         raise TypeError()
 
+    if "cls" not in kwargs:
         kwargs["default"] = _default
     return _orig_json_dumps(*args, **kwargs)