DEP: remove NonNULL attributes from the API interfaces #20971

We use NonNull in the interface API like here

I think this is an anti-pattern since

• These are interface functions. It is on us to actively check NULL input, not to politely suggest that input cannot be NULL.
• The compiler directives generated are only suggestions, and we know how often users relate to warnings
• Some compilers and interface mechanisms have no idea that these hints are there. For instance, these functions are exported from the shared object and can be called by CTypes. How will the compiler hint help?