Feat: Modify the parsing method string to an enumeration type. #5467 (#5468)

### What problem does this PR solve?

Feat: Modify the parsing method string to an enumeration type. #5467

### Type of change


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

web/src/constants/knowledge.ts

@@ -79,4 +79,5 @@ export enum DocumentParserType {
   Audio = 'audio',
   Email = 'email',
   Tag = 'tag',
+  KnowledgeGraph = 'knowledge_graph',
 }