Add Rails 8.2 support

[AlistairNorman]

Desired Behavior

Fix any deprecations for Rails 8.2. Add Rails 8.2 to CI runs. Ensure the application functions as expected.

[AlistairNorman]

Removed the milestone because we don't have a release date for Rails 8.2 yet. @adammathys and I went through the release notes so far and fixed the deprecation we found.

There may be an issue unless it is resolved that kt-paperclip relies on marcel ~> 1.0 and Activestorage now relies on marcel ~> 2.0.