If the --trust-server-cert option is given to svn without the
--non-interactive option, the command fails with an error.
Previously, --non-interactive was always added, but
b1c2cb04 (ExternalProject: Make SVN interactive with
USES_TERMINAL_{DOWNLOAD,UPDATE}, 2022-05-06) changed
the behavior to only add it if the relevant USES_TERMINAL_...
option was set to true.

Fixes: #25197