Audit valid_email gem for Ruby 3.1/3.2

Following #383554 we need to establish if the current version of the valid_email gem we use is compatible with Ruby 3.1/3.2

Audit and fix gitlab-rails dependencies for Rub... (#404750 - closed)

Please see above issue, we need to assess our Ruby gems for Ruby 3.1/3.2 compatibility

Please check when complete and spreadsheet has been updated.

Timeline: As of now we are targeting end of Q3 (end of October) to complete this audit and any related issues that require action.

All Ruby 3.1 related issues can be found here: https://gitlab.com/gitlab-org/gitlab/-/issues/?sort=created_date&state=opened&label_name%5B%5D=Ruby3_1&first_page_size=100

Actions requested

• Check whether the gem's repo is running CI builds against Ruby 3.1/3.2 already.
  • If not submit an MR/PR to add them
• Browse the gem's issue tracker for any signs of Ruby 3 incompatibilities.
• Check if tests pass locally if there is no Ruby 3.1/3.2 build (see #422680 (closed) for an example of this)
• Think about use cases that may not be well-covered with automated tests we already run. An example could be edge cases that only trigger with specific data being used.
  • Manually test these if possible
• Pay special attention to gems that use C-extensions. These talk to internal MRI APIs that may change across major Ruby releases.

Thank you