Fix #142749: Geometry Nodes: Add float4x4 case in get_field_type_name

When hovering on a matrix field socket, `get_field_type_name` can fail
because of missing `float4x4` case. Now it will properly return a
"Matrix Field" name.

Pull Request: https://projects.blender.org/blender/blender/pulls/142794

source/blender/editors/space_node/node_socket_tooltip.cc

@@ -564,6 +564,9 @@ class SocketTooltipBuilder {
     if (base_type.is<math::Quaternion>()) {
       return TIP_("Rotation Field");
     }
+    if (base_type.is<blender::float4x4>()) {
+      return TIP_("Matrix Field");
+    }
     BLI_assert_unreachable();
     return TIP_("Field");
   }