Migration Class Refactor and Column Existence Check

[anilkumarthakur60]

This pull request includes significant updates to our migration scripts, focusing on enhancing maintainability and ensuring robust operations. The primary changes are:

• Refactor to New Migration Class Style: Transitioned migration classes to use anonymous classes extending Migration.
• Enhanced Column Existence Checks: Implemented checks to ensure columns are only added or dropped if they do not already exist or exist, respectively. it also fixes the failing checks in ci with running the migration after publishing when vendor migration file

[selfsimilar]

I would like to see this merged since I manually added the alt column years ago, and the only way to upgrade to to 6.x version is to add a migration to drop my custom alt column first. But if I want to save any alt column data I'll have to also export and then import that column, too. Conditionally adding/removing columns seems like best practice.

[frasmage]

Hi there, sorry for the delay in getting to this. These changes all make sense. Thank you for your contribution!