GDScript: Fix groups and categories been seen as members

modules/gdscript/tests/scripts/runtime/features/groups_are_not_properties.gd

@@ -0,0 +1,9 @@
+# https://github.com/godotengine/godot/issues/73843
+extends RefCounted
+
+@export_group("Resource")
+@export_category("RefCounted")
+
+func test():
+	prints("Not shadowed", Resource.new())
+	prints("Not shadowed", RefCounted.new())

modules/gdscript/tests/scripts/runtime/features/groups_are_not_properties.out

@@ -0,0 +1,3 @@
+GDTEST_OK
+Not shadowed <Resource#-9223371975785708326>
+Not shadowed <RefCounted#-9223371975768931110>