fix: set up dynamic imports correctly

Author: f-aguzzi

pyproject.toml

@@ -71,6 +71,7 @@ docs = ["sphinx==6.0", "furo==2024.5.6"]
 
 # Group 1: Other Language Models
 other-language-models = [
+    "langchain-google-vertexai>=1.0.7",
     "langchain-fireworks>=0.1.3",
     "langchain-groq>=0.1.3",
     "langchain-anthropic>=0.1.11",