Remove unimplemented function declaration (#357)

src/query/stream/streams.hpp

@@ -153,9 +153,6 @@ class Streams final {
                              std::optional<std::chrono::milliseconds> timeout = std::nullopt,
                              std::optional<int64_t> batch_limit = std::nullopt) const;
 
-  /// Return the configuration value passed to memgraph.
-  std::string_view BootstrapServers() const;
-
  private:
   template <Stream TStream>
   using SynchronizedStreamSource = utils::Synchronized<TStream, utils::WritePrioritizedRWLock>;