Regenerated pb2 file.

TensorFlow is now using protobuf>4.
Protobuf>4 requires protobuf-compiler > 3.19.

Used protobuf-compiler 3.21.12-1+build1

Tested locally with protobuf 4.21.12, seems to work.

PiperOrigin-RevId: 509704790

Author: MarkDaoust