feat(next-search): Implements document preview functionality #3221 (#9465)

### What problem does this PR solve?

feat(next-search): Implements document preview functionality

- Adds a new document preview modal component
- Implements document preview page logic
- Adds document preview-related hooks
- Optimizes document preview rendering logic
### Type of change

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

web/src/pages/search/hooks.ts

@@ -135,6 +135,7 @@ export const useSendQuestion = (kbIds: string[]) => {
     answer: currentAnswer,
     relatedQuestions: relatedQuestions?.slice(0, 5) ?? [],
     searchStr,
+    setSearchStr,
     isFirstRender,
     selectedDocumentIds,
     isSearchStrEmpty: isEmpty(trim(searchStr)),