Blender Git Loki

RNA define: check and report invalid usages of ID pointers properties.

Some RNA structs, like operators or keymaps, are not allowed to have ID
pointer properties. now this check will ignore those, and report an
error message in the console.

Related to T82597.

Notes: While a bit more involved than rBf39fbb3e6046, this commit
remains fairly localized and non-intrusive.

It relies on some rather obscure and weird behaviors of our RNA code
though, a cleaner solution could be e.g. to add a tye to
`StructOrFunctionRNA`, so that we could properly 'rebuild' (re-cast) the
pointer to either `StructRNA` or `FunctionRNA` when needed in internal
code...