fix a couple of clippy warnings

Author: imor

src/graphql.rs

@@ -4468,9 +4468,7 @@ fn is_aggregatable(column: &Column, op: &AggregateOperation) -> bool {
 
 /// Returns the appropriate GraphQL scalar type for an aggregate result.
 fn aggregate_result_type(column: &Column, op: &AggregateOperation) -> Option<Scalar> {
-    let Some(ref type_) = column.type_ else {
-        return None;
-    };
+    let type_ = column.type_.as_ref()?;
 
     // Removed duplicated closures, will use helper functions below
 

src/transpile.rs

@@ -1126,10 +1126,7 @@ impl ConnectionBuilder {
 
         // Build aggregate CTE if requested
         let aggregate_cte = if requested_aggregates {
-            let select_list_str = match aggregate_select_list {
-                Some(list) => list,
-                None => String::new(),
-            };
+            let select_list_str = aggregate_select_list.unwrap_or_default();
             format!(
                 r#"
                 ,__aggregates(agg_result) as (