feat(Google Vertex Chat Model Node): Add an option to specify GCP region (#12300)

packages/@n8n/nodes-langchain/nodes/llms/LmChatGoogleVertex/LmChatGoogleVertex.node.ts

@@ -131,6 +131,7 @@ export class LmChatGoogleVertex implements INodeType {
 		const credentials = await this.getCredentials('googleApi');
 		const privateKey = formatPrivateKey(credentials.privateKey as string);
 		const email = (credentials.email as string).trim();
+		const region = credentials.region as string;
 
 		const modelName = this.getNodeParameter('modelName', itemIndex) as string;
 
@@ -165,6 +166,7 @@ export class LmChatGoogleVertex implements INodeType {
 						private_key: privateKey,
 					},
 				},
+				location: region,
 				model: modelName,
 				topK: options.topK,
 				topP: options.topP,