Python gen for array within struct not set to staticmethod for length/isnone

The ...Length and ...IsNone functions are constant for an array within a struct (which is kind of the point I think?) so the functions should be static in the py and pyi. These are located:
https://github.com/google/flatbuffers/blob/bab10754d93d74d1ff44d46de63558bc4127f7d8/src/idl_gen_python.cpp#L481-L482

https://github.com/google/flatbuffers/blob/bab10754d93d74d1ff44d46de63558bc4127f7d8/src/idl_gen_python.cpp#L804

and

https://github.com/google/flatbuffers/blob/bab10754d93d74d1ff44d46de63558bc4127f7d8/src/idl_gen_python.cpp#L825