Change additionalProperties type to Any

This is aligned with "default" which is also `Any`, and both in vertex ai docs:
https://cloud.google.com/vertex-ai/docs/reference/rest/v1/projects.locations.cachedContents#Schema

are both with 'value' type

litellm/types/llms/vertex_ai.py

@@ -113,7 +113,7 @@ class Schema(TypedDict, total=False):
     pattern: str
     example: Any
     anyOf: List["Schema"]
-    additionalProperties: bool
+    additionalProperties: Any
 
 
 class FunctionDeclaration(TypedDict, total=False):