Fix Voyage re-rank model. Limit file name length. (#4171)

### What problem does this PR solve?

#4152 
#4154

### Type of change

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

api/db/services/file_service.py

                 MAX_FILE_NUM_PER_USER = int(os.environ.get('MAX_FILE_NUM_PER_USER', 0))
                 if MAX_FILE_NUM_PER_USER > 0 and DocumentService.get_doc_count(kb.tenant_id) >= MAX_FILE_NUM_PER_USER:
                     raise RuntimeError("Exceed the maximum file number of a free user!")
+                if len(file.filename) >= 128:
+                    raise RuntimeError("Exceed the maximum length of file name!")
 
                 filename = duplicate_name(
                     DocumentService.query,

rag/llm/rerank_model.py

         self.model_name = model_name
 
     def similarity(self, query: str, texts: list):
+        rank = np.zeros(len(texts), dtype=float)
+        if not texts:
+            return rank, 0
         res = self.client.rerank(
             query=query, documents=texts, model=self.model_name, top_k=len(texts)
         )
-        rank = np.zeros(len(texts), dtype=float)
         for r in res.results:
             rank[r.index] = r.relevance_score
         return rank, res.total_tokens