fix: add type annotations to InputValidationError

Author: blueeye-040

src/google/adk/artifacts/gcs_artifact_service.py

@@ -232,12 +232,10 @@ def _save_artifact(
       )
     elif artifact.file_data:
       if not artifact.file_data.file_uri:
-        raise InputValidationError(  # type: ignore[no-untyped-call]
-            "Artifact file_data must have a file_uri."
-        )
+        raise InputValidationError("Artifact file_data must have a file_uri.")
       if artifact_util.is_artifact_ref(artifact):
         if not artifact_util.parse_artifact_uri(artifact.file_data.file_uri):
-          raise InputValidationError(  # type: ignore[no-untyped-call]
+          raise InputValidationError(
               f"Invalid artifact reference URI: {artifact.file_data.file_uri}"
           )
       # Store the URI as blob metadata; no content to upload.

src/google/adk/errors/input_validation_error.py

@@ -18,7 +18,7 @@
 class InputValidationError(ValueError):
   """Represents an error raised when user input fails validation."""
 
-  def __init__(self, message="Invalid input."):
+  def __init__(self, message: str = "Invalid input.") -> None:
     """Initializes the InputValidationError exception.
 
     Args: