Document callback URI application updates

[AaronDDM]

Context

Follow-up to the review feedback on nylas-java#327. Ruby already forwards raw request hashes for Applications#update, so callers can send callback_uris entries with existing ids. This PR adds explicit parity coverage and documentation.

Summary

• Document that Applications#update can preserve existing callback URIs by passing callback_uris entries with id.
• Add focused coverage that callback_uris with id are forwarded unchanged.
• Document Workspaces#auto_group filters, including invalid_also.
• Update the Unreleased changelog for callback URI preservation and workspace auto-group filters.

Testing

• bundle exec rspec spec/nylas/resources/applications_spec.rb spec/nylas/resources/workspaces_spec.rb
• GitHub Actions: passing

[qasim-nylas]

LGTM 👍