Is static_assert in intrusive_ptr required?

https://github.com/DymOK93/KTL/blob/master/include/smart_pointer.hpp#L1357
Often this compile-time assertion gets in the way of finding the real cause of a compilation error.

Example:
```c++
template
class ContextBase {...};

template
void intrusive_ptr_add_ref(ContextBase* ptr) {...};

template
void intrusive_ptr_release(ContextBase* ptr) noexcept {...};

class SomeContext : ContextBase {...}; // Oops... Private inheritance due to a typo
```
In the case of a large project, it becomes almost impossible to debug this compilation error.
What do you think, @GeorgyFirsov?