Resource provider mistakenly disposed on class unload

If a template class is associated to a template script which uses a resource provider, the resource provider is mistakenly disposed when unloading the template class (even if the template script is still loaded).
This is an issue especially in some skin reloads scenarios, in which the template script is not reloaded, while the template class is reloaded, which leads to a situation in which the reloaded template can no longer use the resource provider which was mistakenly disposed.