feat: add ingestion pipeline children delimiters configs (#11979)

### What problem does this PR solve?

Add children delimiters for Ingestion pipeline config

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/components/chunk-method-dialog/use-default-parser-values.ts

@@ -12,6 +12,8 @@ export function useDefaultParserValues() {
       layout_recognize: ParseDocumentType.DeepDOC,
       chunk_token_num: 512,
       delimiter: '\n',
+      enable_children: false,
+      children_delimiter: '\n',
       auto_keywords: 0,
       auto_questions: 0,
       html4excel: false,