PRO-2504 avoid combining $not with $regex in older mongodb

[boutell]

Summary

See changelog.

What are the specific steps to test this change?

See previous PR, but I've tested it, code review would be sufficient given current resourcing.

What kind of change does this PR introduce?

• [X] Bug fix
• [ ] New feature
• [ ] Refactor
• [ ] Documentation
• [ ] Build-related changes
• [ ] Other

Make sure the PR fulfills these requirements:

• [X] It includes a) the existing issue ID being resolved, b) a convincing reason for adding this feature, or c) a clear description of the bug it resolves
• [X] The changelog is updated
• [ ] Related documentation has been updated
• [ ] Related tests have been updated

If adding a new feature without an already open issue, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[linear[bot]]

PRO-2504 [P'unk] Getting Snap Redirects

See details here: [https://apostrophecms.atlassian.net/browse/SD-393](https://apostrophecms.atlassian.net/browse/SD-393) 1\. Removing redirects from workflow: gettingsnap.org has redirects under Workflow, and we would like them to be excluded.\ 2\. Consolidating Redirects: On gettingsnap.org, there are currently redirects both in the application and in Mechanic, which were implemented as a stopgap. Once the redirects are out of Workflow, we’d like to consolidate these in whatever method Apostrophe suggests. \ 3\. Testing