fix docker builds to run gem update system with gem-update pinned to specific version that is compatible with ruby 2.7

[yuenmichelle1]

run gem update system so installation of mini_racer does not fail https://github.com/rubyjs/mini_racer?tab=readme-ov-file#supported-ruby-versions--troubleshooting

pinning gem update to 3.4.22 since using default gem-update requires updating Ruby version to 3+. See: #4271

Review checklist

• First, the most important one: is this PR small enough that you can actually review it? Feel free to just reject a branch if the changes are hard to review due to the length of the diff.
• If there are any migrations, will they the previous version of the app work correctly after they've been run (e.g. the don't remove columns still known about by ActiveRecord).
• If anything changed with regards to the public API, are those changes also documented in the apiary.apib file?
• Are all the changes covered by tests? Think about any possible edge cases that might be left untested.