fix: add fallback parser list for empty parser_ids (#12632)

### What problem does this PR solve?

Fixes #12570 - The slicing method dropdown was empty when deploying
RAGFlow v0.23.1 from source code.

The issue occurred because `parser_ids` from the tenant info was empty
or undefined, causing `useSelectParserList` to return an empty array.
This PR adds a fallback to a default parser list when `parser_ids` is
empty, ensuring the dropdown always has options.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---
Contribution by Gittensor, see my contribution statistics at
https://gittensor.io/miners/details?githubId=94194147

web/src/hooks/use-user-setting-request.tsx

@@ -112,6 +112,23 @@ export const useFetchTenantInfo = (
   return { data, loading };
 };
 
+const DEFAULT_PARSERS = [
+  { value: 'naive', label: 'General' },
+  { value: 'qa', label: 'Q&A' },
+  { value: 'resume', label: 'Resume' },
+  { value: 'manual', label: 'Manual' },
+  { value: 'table', label: 'Table' },
+  { value: 'paper', label: 'Paper' },
+  { value: 'book', label: 'Book' },
+  { value: 'laws', label: 'Laws' },
+  { value: 'presentation', label: 'Presentation' },
+  { value: 'picture', label: 'Picture' },
+  { value: 'one', label: 'One' },
+  { value: 'audio', label: 'Audio' },
+  { value: 'email', label: 'Email' },
+  { value: 'tag', label: 'Tag' },
+];
+
 export const useSelectParserList = (): Array<{
   value: string;
   label: string;
@@ -120,7 +137,13 @@ export const useSelectParserList = (): Array<{
 
   const parserList = useMemo(() => {
     const parserArray: Array<string> = tenantInfo?.parser_ids?.split(',') ?? [];
-    return parserArray.map((x) => {
+    const filteredArray = parserArray.filter((x) => x.trim() !== '');
+
+    if (filteredArray.length === 0) {
+      return DEFAULT_PARSERS;
+    }
+
+    return filteredArray.map((x) => {
       const arr = x.split(':');
       return { value: arr[0], label: arr[1] };
     });