fix: Added Missing imports into __init__.py (#36)

libs/vertexai/langchain_google_vertexai/__init__.py

@@ -1,6 +1,7 @@
 from langchain_google_vertexai._enums import HarmBlockThreshold, HarmCategory
 from langchain_google_vertexai.chains import create_structured_runnable
 from langchain_google_vertexai.chat_models import ChatVertexAI
+from langchain_google_vertexai.embeddings import VertexAIEmbeddings
 from langchain_google_vertexai.functions_utils import PydanticFunctionsOutputParser
 from langchain_google_vertexai.gemma import (
     GemmaChatLocalHF,