Upgrade our apps to rails 7.2

[AgaDufrat]

How

https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#upgrading-from-rails-7-1-to-rails-7-2

• Run rails app:update command and review changes
• Use 7.2 defaults
• Fix deprecation warnings

### Tasks
- [ ] https://github.com/alphagov/support-api/pull/1054
- [ ] Content Data Admin
- [ ] Content Data API
- [ ] Release
- [ ] Support

Suggested steps we followed for Rails 7.0 upgrades

1. Update Rails version

• Run rails app:update and accept all changes (press a).
• Run rubocop -A to auto-fix any stylistic differences between the Rails defaults and our linter rules.
• Review in git and keep/discard changes as appropriate.
• Try to retain any config values that seem to have been set for a reason, while keeping new values that replace old defaults. Git blame is helpful here – for example to determine if particular lines were set for a reason, or if they haven’t been touched since the codebase was first generated.
• Run the test suite to make sure it still passes – ignore deprecation notices, we'll fix them in the next step.
• Commit changes: git commit -am "Run rails app:update"

2. Fix deprecation notices

• Run the test suite and look out for deprecation notices shown in the console.
• Fix all deprecations. Note that some deprecations may come from other GOV.UK gems, which will need to be resolved in a separate piece of work. It's worth taking a note of them, though, as they can be turned into Trello cards.
• Commit changes: git commit -am "Fix deprecation notices"