Fix bug of image parser and prompt of parser supports customization (#10319)

### What problem does this PR solve?
BugFix: ERROR: KeyError: 'llm_id'
Feat: The prompt of the describe picture in cv_model supports
customization #10320


### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/data-flow/form/parser-form/index.tsx

@@ -64,6 +64,7 @@ export const FormSchema = z.object({
       lang: z.string().optional(),
       fields: z.array(z.string()).optional(),
       llm_id: z.string().optional(),
+      system_prompt: z.string().optional(),
     }),
   ),
 });