Do not enqueue PAT expiry enforcement migration

What does this MR do and why?

This MR drops a migration that added an expiration to all tokens that did not have one, and set it to 1 year from May 22nd 2023. Due to the impact on users, the backport drop the migration to avoid interruption to user workflows without them realizing it. There is considerable discussion on options, and whether these backports will indeed be merged in the related issue.

Note this is only being merged for SM users as the migration will already be run for users on GitLab.com

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/462157+

These migrations were removed from the default branch in 16.10 . Other changes to specs in the default branch have been cherry-picked to handle date-specific specs and build errors unrelated to the removed migrations.

MR acceptance checklist

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

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).
• Set the milestone of the merge request to match the target backport branch version.
• This MR has been approved by a maintainer (only one approval is required).
• Ensure the e2e:package-and-test-ee job has either succeeded or been approved by a Software Engineer in Test.

Note to the merge request author and maintainer

If you have questions about the patch release process, please:

• Refer to the patch release runbook for engineers and maintainers for guidance.
• Ask questions on the #releases Slack channel (internal only).