In the kdelibs to KF5 transition a factory class was added for loading
the rename prompts to make KIO gui-less.
In jobs "if (isInteractive)" was changed everywhere into "if
(uiDelegateExtension)".
The former was false if we called KJob::setUiDelegate(nullptr). The
latter is only false if the calling code explicitly calls the new
KIO::Job::setUiDelegateExtension(nullptr) as well.
This left kioclient5 in the very weird state of non-interactive mode
still having rename dialogs but not error messages.
Now non-interactive mode will simply error if it hits a conflict and
stop as before.