Compositor: Hide value of Image Info node input

The Image Info node has no meaning when nothing is connected to the
input. So hide its value to make this more clear.

source/blender/nodes/composite/nodes/node_composite_image_info.cc

@@ -15,7 +15,7 @@ namespace blender::nodes::node_composite_image_info_cc {
 
 static void node_declare(NodeDeclarationBuilder &b)
 {
-  b.add_input<decl::Color>("Image").compositor_realization_mode(
+  b.add_input<decl::Color>("Image").hide_value().compositor_realization_mode(
       CompositorInputRealizationMode::None);
 
   b.add_output<decl::Vector>("Dimensions")