fix: replace bare except with except Exception (#22473)

Replace bare except clauses with except Exception to follow Python best practices and avoid catching unexpected system exceptions like KeyboardInterrupt and SystemExit.

backend/open_webui/retrieval/vector/dbs/chroma.py

@@ -123,7 +123,7 @@ class ChromaClient(VectorDBBase):
                     }
                 )
             return None
-        except:
+        except Exception:
             return None
 
     def get(self, collection_name: str) -> Optional[GetResult]: