Can't call get_module_infos() on if main module file included already

Any module file that has been included already cannot be used in the get_module_infos() function.

This is because it checks if (!class_exists($info_class)) and only appends _info to the class name if the class does not exist (around line 595).

I am not sure if info classes are always required to end in _info or not (especially with extensions), so I'm not creating a PR for this, but this should be fixed soon as it can cause problems and cause problems during updates with migrations.