docs: Add Databricks integration (#25929)

Updating the gateway pages in the documentation to name the
`langchain-databricks` integration.

---------

Signed-off-by: B-Step62 <yuki.watanabe@databricks.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

docs/scripts/partner_pkg_table.py

@@ -15,6 +15,7 @@ EXTERNAL_PACKAGES = {
     "astradb",
     "aws",
     "cohere",
+    "databricks",
     "elasticsearch",
     "google-community",
     "google-genai",