fix(core): Pg-promise de-initialization fix (#7417)

Github issue / Community forum post (link here to close automatically):

https://community.n8n.io/t/postgres-node-called-end-on-pool-more-than-once/30585/1

packages/nodes-base/nodes/Microsoft/Sql/MicrosoftSql.node.ts

@@ -440,7 +440,7 @@ export class MicrosoftSql implements INodeType {
 			}
 		}
 
-		// Close the connection
+		// shuts down the connection pool associated with the db object to allow the process to finish
 		await pool.close();
 
 		const itemData = generatePairedItemData(items.length);