fix(converter): handle serialization of recursive exceptions

It is kind of an easy mistake to do in python:

```
try:
    raise ValueError("test")
except Exception as e:
    raise e from e
```

The reraised exception will have e.__cause__ referencing itself resulting in failure to serialize error and python sdk won't report anything resulting in retries and startToClose timeouts.

Author: German Ilin

temporalio/converter.py

@@ -800,7 +800,8 @@ def to_failure(
                 str(exception), type=exception.__class__.__name__
             )
             failure_error.__traceback__ = exception.__traceback__
-            failure_error.__cause__ = exception.__cause__
+            if exception.__cause__ and exception.__cause__ != exception:
+                failure_error.__cause__ = exception.__cause__
             self._error_to_failure(failure_error, payload_converter, failure)
         # Encode common attributes if requested
         if self._encode_common_attributes:

tests/test_converter.py

@@ -490,6 +490,20 @@ async def decode(self, payloads: Sequence[Payload]) -> List[Payload]:
         return list(wrapper.payloads)
 
 
+async def test_broken_exception_serialization():
+    conv = DataConverter(
+        payload_codec=SimpleCodec(),
+    )
+    try:
+try:
+    raise ValueError("test")
+except Exception as e:
+    raise e from e
+    except Exception as e:
+        failure = Failure()
+        conv.failure_converter.to_failure(e, conv.payload_converter, failure)
+
+
 async def test_failure_encoded_attributes():
     try:
         raise ApplicationError("some message", "some detail")