The GCSToLocalFilesystemOperator in Google Provider <=3.0.0  had wrong import for apply_defaults. It used

```
from airflow.sensors.base_sensor_operator import apply_defaults
```

instead of 

```
from airflow.utils.decorators import apply_defaults
```

When we removed `apply_defaults` in #15667, the base_sensor_operator import was removed as well which made the GCSToLocalFilestystemOperator stops working in 2.1.0

The import in base_sensor_operator will be restored in 2.1.1  and Google Provider 4.0.0 will work without problems after it is released. Workaround for 2.1.0 Airflow is to copy the code of the operator to DAG and use it temporarily until new versions are released. 
airflow/sensors/base.py
"""
    Class Decorator for child classes of BaseSensorOperator to indicate
    that instances of this class are only safe to use poke mode.
    Will decorate all methods in the class to assert they did not change
    the mode from 'poke'.
    :param cls: BaseSensor class to enforce methods only use 'poke' mode.
    :type cls: type
    """
    def decorate(cls_type):
        def mode_getter(_):
            return 'poke'
        def mode_setter(_, value):
            if value != 'poke':
                raise ValueError("cannot set mode to 'poke'.")
        if not issubclass(cls_type, BaseSensorOperator):
            raise ValueError(
                f"poke_mode_only decorator should only be "
                f"applied to subclasses of BaseSensorOperator,"
                f" got:{cls_type}."
            )
        cls_type.mode = property(mode_getter, mode_setter)
        return cls_type
    return decorate(cls)
if 'BUILDING_AIRFLOW_DOCS' in os.environ:
    
    
    apply_defaults = lambda x: x