chore(deps): update dependency langchain-google-vertexai to v3.0.3 (#2011)

This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
|
[langchain-google-vertexai](https://redirect.github.com/langchain-ai/langchain-google)
([source](https://redirect.github.com/langchain-ai/langchain-google/tree/HEAD/libs/vertexai),
[changelog](https://redirect.github.com/langchain-ai/langchain-google/releases?q=%22vertexai%22))
| `==3.0.2` -> `==3.0.3` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/langchain-google-vertexai/3.0.3?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/langchain-google-vertexai/3.0.2/3.0.3?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

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Co-authored-by: Harsh Jha <[email protected]>

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docs/en/getting-started/quickstart/python/langchain/requirements.txt

@@ -1,5 +1,5 @@
 langchain==1.0.8
-langchain-google-vertexai==3.0.2
+llangchain-google-vertexai==3.0.3
 langgraph==1.0.3
 toolbox-langchain==0.5.3
 pytest==9.0.1