interfaces: drop the conditional import of the vendored `zope` packages...
interfaces: drop the conditional import of the vendored `zope` packages
The real `zope` code was only used when enabled by a test, and the decorators
turned into no-ops at runtime. Now that the test is disabled, unconditionally
use the no-op decorators and stop importing the code. This module can go away
once the `mercurial.interfaces.repository` interfaces are converted to Protocol
classes, but the vendored code can be deleted in the meantime.