Bump Rails 7.2

[pgwillia]

https://edgeguides.rubyonrails.org/7_2_release_notes.html

May be dependent on comfy.

[murny]

Looks like we can't do this until we migrate off of secrets

From https://edgeguides.rubyonrails.org/7_2_release_notes.html#railties-removals:

Remove deprecated Rails.application.secrets.

You can see this failing in the dependabot PR: https://github.com/ualbertalib/library-cms/actions/runs/10374144119/job/28720917903

I posted some ideas for doing this in the Jupiter Issue: ualbertalib/jupiter#3347

Either we need to go to credentials which replaced secrets (but this requires coordination with Neil and changing how we do things for deployments) or basically create our own "secrets" config for the time being, like using a simple config_for. Or maybe explore some other options.