Fix mypy errors for RayHook

[amoghrajesh]

Mypy 1.19 started complaining of:

  providers/google/src/airflow/providers/google/cloud/hooks/vertex_ai/ray.py:56: error: Argument 1 to "asdict" has incompatible type "DataclassInstance | type[DataclassInstance]"; expected
  "DataclassInstance"  [arg-type]
                      return dataclasses.asdict(value)
                                                ^~~~~
  Found 1 error in 1 file (checked 4046 source files)

  Error 1 returned
  You are running mypy with the folders selected. If you want to reproduce it locally, you need to run the following command:

The error is because mypy is stricter about this now. The issue is that dataclass.isdataclass returns True for both classes and instances: https://docs.python.org/3/library/dataclasses.html#dataclasses.is_dataclass and this causes a runtime error because dataclass.asdict can only be used on instances.

To ensure that fix doesnt break functionality, this is what I checked:

Python 3.13.3 (main, Apr  8 2025, 13:54:08) [Clang 17.0.0 (clang-1700.0.13.3)] on darwin
import dataclasses
@dataclasses.dataclass
class Example:
    name: str
instance = Example(name="test")
class_type = Example
dataclasses.is_dataclass(instance)
Out[3]: True
dataclasses.is_dataclass(class_type)
Out[4]: True
dataclasses.is_dataclass(instance) and not isinstance(instance, type)
Out[5]: True
dataclasses.is_dataclass(class_type) and not isinstance(class_type, type)
Out[6]: False
    
if dataclasses.is_dataclass(class_type) and not isinstance(class_type, type):
    print("I am here")
    print(dataclasses.asdict(class_type))
    
if dataclasses.is_dataclass(instance) and not isinstance(instance, type):
    print(dataclasses.asdict(instance))
    
{'name': 'test'}

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