Revert "Reset repository checksum before publishing an updated event"

Purpose of revert

This reverts merge request !139282 (merged), since I found the following error in the staging-ref while validating these changes. We don't need to backport this since we did not release %16.8 yet.

irb(main):046:0> p.geo_handle_after_update
/srv/gitlab/vendor/bundle/ruby/3.1.0/gems/activerecord-7.0.8/lib/active_record/validations.rb:80:in `raise_validation_error': Validation failed: Verification checksum can't be blank (ActiveRecord::RecordInvalid)
irb(main):047:0> command terminated with exit code 137

Checklist

• [-] Create an issue to reinstate the merge request and assign it to the author of the reverted merge request.
• [-] If the revert is to resolve a broken 'master' incident, please read through the Responsibilities of the Broken master resolution DRI.
• [-] If the revert involves a database migration, please read through Deleting existing migrations.
• [-] Add the appropriate labels before the MR is created. We can skip CI/CD jobs only if the labels are added before the CI/CD pipeline is created.

Milestone info

• I am reverting something in the current milestone. No changelog is needed, and I've added a ~"regression:*" label.
• I am reverting something in a different milestone. A changelog is needed, and I've removed the ~"regression:*" label.

Related issues and merge requests

#427493 (closed)