feat: Added the VertexAiResourceNoun.to_dict() method

This method allows getting the resource metadata as a standard Python dictionary.
Without this method, any user who would want to do this would have to access private fields.

google/cloud/aiplatform/base.py

@@ -44,6 +44,7 @@
 from google.cloud.aiplatform import initializer
 from google.cloud.aiplatform import utils
 from google.cloud.aiplatform.compat.types import encryption_spec as gca_encryption_spec
+from google.protobuf import json_format
 
 logging.basicConfig(level=logging.INFO, stream=sys.stdout)
 
@@ -607,6 +608,10 @@ def _assert_gca_resource_is_available(self) -> None:
     def __repr__(self) -> str:
         return f"{object.__repr__(self)} \nresource name: {self.resource_name}"
 
+    def to_dict(self) -> dict:
+        """Returns the resource proto as a dictionary."""
+        return json_format.MessageToDict(self.gca_resource._pb)
+
 
 def optional_sync(
     construct_object_on_arg: Optional[str] = None,