DPL-876 As PSD we would like to upgrade GateKeeper to Ruby 3 and Rails 7 so that we keep up to date with our dependencies.

[TWJW-SANGER]

Describe the Housekeeping
As PSD we would like to upgrade GateKeeper to Ruby 3 and Rails 7 so that we keep up to date with our dependencies.

Blocking issues
We need to do this if we don't do #100

• Review and update any other dependencies that require updating as part of this process.
• Ensure any existing unit and integration tests pass

[KatyTaylor]

I've put this as medium because a) it's already on Ruby 3, and b) if we do it after sanger/samples_extraction#277 then we'll have prior experience upgrading to Rails 7.

[TWJW-SANGER]

Closing this as it is in Done