Geometry Nodes: refactor geometry nodes execution interface

The main goal of this refactor is to simplify how a geometry node group is executed.
Previously, there was duplicated logic that turned the lazy-function graph of a node
group into a single lazy-function. Now this is done only in one place and others can
just execute the lazy-function directly, without having to worry about the underlying graph.

Pull Request: https://projects.blender.org/blender/blender/pulls/112482

source/blender/functions/intern/lazy_function_graph_executor.cc

@@ -1503,17 +1503,13 @@ void GraphExecutor::destruct_storage(void *storage) const
 std::string GraphExecutor::input_name(const int index) const
 {
   const lf::OutputSocket &socket = *graph_inputs_[index];
-  std::stringstream ss;
-  ss << socket.node().name() << " - " << socket.name();
-  return ss.str();
+  return socket.name();
 }
 
 std::string GraphExecutor::output_name(const int index) const
 {
   const lf::InputSocket &socket = *graph_outputs_[index];
-  std::stringstream ss;
-  ss << socket.node().name() << " - " << socket.name();
-  return ss.str();
+  return socket.name();
 }
 
 void GraphExecutorLogger::log_socket_value(const Socket &socket,