fix: add missing idle_timeout_secs in ConnectionConfig constructors and fix clippy warnings

crates/dbx-core/src/cloud_sync.rs

@@ -576,6 +576,7 @@ mod tests {
             })],
             connect_timeout_secs: 5,
             query_timeout_secs: 30,
+            idle_timeout_secs: 60,
             ssl: false,
             ca_cert_path: String::new(),
             client_cert_path: String::new(),