Fix support for older versions of zope-interface

[devonh]

Fixes #19269

Versions of zope-interface from RHEL, Ubuntu LTS 22 & 24 and OpenSuse don't support the new python union X | Y syntax for interfaces. This PR partially reverts the change over to fully use the new syntax, adds a minimum supported version of zope-interface to Synapse's dependency list, and removes the linter auto-upgrades which prefer the newer syntax.

Pull Request Checklist

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