Remove unused updated_state_by_user_id from merge_request_reviewers

What does this MR do and why?

This MR removes updated_state_by_user_id from merge_request_reviewers as it is no longer used since attention request feature has been removed. This field has been set to be ignored since !96324 (merged) (merged)

Related to #371476 (closed)

Migration output

Up

main: == 20220919041604 DropUnusedFieldsFromMergeRequestReviewers: migrating ========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- column_exists?(:merge_request_reviewers, :updated_state_by_user_id)
main:    -> 0.0027s
main: -- remove_column(:merge_request_reviewers, :updated_state_by_user_id)
main:    -> 0.0022s
main: == 20220919041604 DropUnusedFieldsFromMergeRequestReviewers: migrated (0.0090s) 

Down

main: == 20220919041604 DropUnusedFieldsFromMergeRequestReviewers: reverting ========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- column_exists?(:merge_request_reviewers, :updated_state_by_user_id)
main:    -> 0.0061s
main: -- add_column(:merge_request_reviewers, :updated_state_by_user_id, :bigint)
main:    -> 0.0012s
main: -- transaction_open?()
main:    -> 0.0009s
main: -- index_exists?(:merge_request_reviewers, :updated_state_by_user_id, {:name=>"index_on_merge_request_reviewers_updated_state_by_user_id", :algorithm=>:concurrently})
main:    -> 0.0087s
main: -- execute("SET statement_timeout TO 0")
main:    -> 0.0006s
main: -- add_index(:merge_request_reviewers, :updated_state_by_user_id, {:name=>"index_on_merge_request_reviewers_updated_state_by_user_id", :algorithm=>:concurrently})
main:    -> 0.0023s
main: -- execute("RESET statement_timeout")
main:    -> 0.0006s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- foreign_keys(:merge_request_reviewers)
main:    -> 0.0059s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE merge_request_reviewers\nADD CONSTRAINT fk_3d674b9f23\nFOREIGN KEY (updated_state_by_user_id)\nREFERENCES users (id)\nON DELETE SET NULL\nNOT VALID;\n")
main:    -> 0.0030s
main: -- execute("ALTER TABLE merge_request_reviewers VALIDATE CONSTRAINT fk_3d674b9f23;")
main:    -> 0.0022s
main: == 20220919041604 DropUnusedFieldsFromMergeRequestReviewers: reverted (0.0815s) 

MR acceptance checklist

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

Related to #371476 (closed)