Upgrade Validate to reduce file size

[lognaturel]

Addresses comments at #720 (comment)

Updates changelog in preparation for release

Verified this using https://docs.google.com/spreadsheets/d/1FOlADSaTTUOhsbeQDcU5HZrJfzseVYwBMdTIz1Skmkw/edit?gid=1068911091#gid=1068911091

Why is this the best possible solution? Were any other approaches considered?

This reduces Validate's size down to 3.9 MB. I think that's a good balance between benefit and time spent for now. We can come back to getodk/validate#92

What are the regression risks?

Most likely would be with the extract-signed function but I think the form I tried is enough.

Does this change require updates to documentation? If so, please file an issue here and include the link below.

No.

Before submitting this PR, please make sure you have:

• included test cases for core behavior and edge cases in tests
• run python -m unittest and verified all tests pass
• run ruff format pyxform tests and ruff check pyxform tests to lint code
• verified that any code or assets from external sources are properly credited in comments

[lindsay-stevens]

Amazing!