fix(csharp): address issue #546 (1 review thread)

Addresses:
  - #3463183641 at csharp/src/StatementExecution/StatementExecutionStatement.cs:1187

Author: peco-engineer-bot[bot]

csharp/src/StatementExecution/StatementExecutionStatement.cs

@@ -1186,7 +1186,7 @@ private async Task<QueryResult> GetTablesAsync(CancellationToken cancellationTok
                 var refGenBuilder = new StringArray.Builder();
                 // Type-name comparison is case-sensitive against the uppercase server
                 // types (TABLE/VIEW/SYSTEM TABLE/...), matching JDBC's exact
-                // Arrays.asList(types).contains(...) and the Thrift path. An empty/whitespace
+                // Arrays.asList(types).contains(...) and the Thrift path. A null or empty
                 // filter means "all types" (handled by IsNullOrEmpty above), also matching JDBC.
                 var tableTypeFilter = !string.IsNullOrEmpty(_metadataTableTypes)
                     ? new HashSet<string>(