Replace `WindowUDFImpl::{equals,hash_value}` with `UdfHash`, `UdfEq` traits

[findepi]

Implement proposal set forth in #16677 (comment) for WindowUDFImpl (UDWF)

• depends on Replace ScalarUDFImpl::{equals,hash_value} with UdfHash, UdfEq traits #16871 for traits to exist
• depends on Implement PartialEq, Hash for all UDWFs (WindowUDFImpl) #16870 for PartialEq, Hash to be already implemented for these functions