fix: resolve issue delete column null on after update event subscriber

[spotykatch]

Fixes: #6327
Fixes: #6349

Rewrite this one pr #8227

Description of change

Subscriber afterUpdate now gets entity with changed delete and update date column.

Adds getSoftDeletionReturningColumns method to ReturningResultsEntityUpdator class to get right returning columns and search for entity withDeleted(). Resolves bug in SubjectExecutor class. Adds tests for the issue.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run lint passes with this change
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md

[spotykatch]

CircleCI https://app.circleci.com/pipelines/github/spotykatch/typeorm-1?branch=1

[pleerock]

Thank you!