Drop `last_edited_at` Column From Vulnerabilities

What does this MR do and why?

last_edited_at is an ignored column (source)

This MR drops the column for step 2 of the 3-MR drop column process

Check for indexes or constraints

Using the command \d+ vulnerabilities on postgres.ai indicates there are NOT indexes and constraints

index	fk constraint

migration output

bundle exec rails db:migrate output

~/gitlab-development-kit/gitlab$ bundle exec rails db:migrate
main: == [advisory_lock_connection] object_id: 183120, pg_backend_pid: 1059121
main: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: migrating ======
main: -- remove_column(:vulnerabilities, :last_edited_at)
main:    -> 0.0036s
main: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: migrated (0.0066s) 

main: == [advisory_lock_connection] object_id: 183120, pg_backend_pid: 1059121
ci: == [advisory_lock_connection] object_id: 183360, pg_backend_pid: 1059123
ci: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: migrating ======
ci: -- remove_column(:vulnerabilities, :last_edited_at)
ci:    -> 0.0011s
ci: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: migrated (0.0074s) 

ci: == [advisory_lock_connection] object_id: 183360, pg_backend_pid: 1059123

bundle exec rails db:rollback:main output

~/gitlab-development-kit/gitlab$ bundle exec rails db:rollback:main
main: == [advisory_lock_connection] object_id: 182900, pg_backend_pid: 1061708
main: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: reverting ======
main: -- add_column(:vulnerabilities, :last_edited_at, :datetime_with_timezone)
main:    -> 0.0013s
main: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: reverted (0.0041s) 

main: == [advisory_lock_connection] object_id: 182900, pg_backend_pid: 1061708

bundle exec rails db:rollback:ci output

~/gitlab-development-kit/gitlab$ bundle exec rails db:rollback:ci
ci: == [advisory_lock_connection] object_id: 182840, pg_backend_pid: 1061226
ci: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: reverting ======
ci: -- add_column(:vulnerabilities, :last_edited_at, :datetime_with_timezone)
ci:    -> 0.0013s
ci: == 20231220130725 RemoveLastEditedAtColumnFromVulnerabilities: reverted (0.0088s) 

ci: == [advisory_lock_connection] object_id: 182840, pg_backend_pid: 1061226

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #268154 (closed)