Fix change_column_type_concurrently for migration v2

What does this MR do and why?

Fix the migration helper change_column_type_concurrently

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Before	After

How to set up and validate locally

• Run migration generator to run change_column_type_concurrently: rails g post_deployment_migration change_column_type_testing

• Change the migration files:

  class ChangeColumnTypeTesting < Gitlab::Database::Migration[2.2]
    milestone '16.7'
    disable_ddl_transaction!
  
    def up
      change_column_type_concurrently(:ci_pipelines, :lock_version, :text)
    end
  
    def down
    end
  end

• Execute the migrations using scripts/regenerate-schema

• Check if the migrations update db/structure.sql correctly and add the new column lock_version_for_type_change and associated triggers and constraints.

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 #422316 (closed) #383072