sqld: use unexpanded SQL for top queries

... so that we don't distinguish between different bound values
when tracking queries, and instead only gather information
about the raw query string that may contain wildcards, like:
 INSERT INTO t VALUES (?, ?, ?);

libsql-server/src/connection/libsql.rs

@@ -606,7 +606,7 @@ impl<W: WalHook> Connection<W> {
 
         drop(qresult);
 
-        self.update_stats(&stmt);
+        self.update_stats(query.stmt.stmt.clone(), &stmt);
 
         Ok((affected_row_count, last_insert_rowid))
     }
@@ -640,7 +640,7 @@ impl<W: WalHook> Connection<W> {
         Ok(())
     }
 
-    fn update_stats(&self, stmt: &rusqlite::Statement) {
+    fn update_stats(&self, sql: String, stmt: &rusqlite::Statement) {
         let rows_read = stmt.get_status(StatementStatus::RowsRead);
         let rows_written = stmt.get_status(StatementStatus::RowsWritten);
         let rows_read = if rows_read == 0 && rows_written == 0 {
@@ -652,9 +652,8 @@ impl<W: WalHook> Connection<W> {
         self.stats.inc_rows_written(rows_written as u64);
         let weight = (rows_read + rows_written) as i64;
         if self.stats.qualifies_as_top_query(weight) {
-            let query = stmt.expanded_sql().unwrap_or("<unknown>".into());
             self.stats
-                .add_top_query(crate::stats::TopQuery::new(query, rows_read, rows_written));
+                .add_top_query(crate::stats::TopQuery::new(sql, rows_read, rows_written));
         }
     }