fail to display unlock dialog with glib 2.70

After upgrading to glib 2.70 the unlock dialog does not show up.

When running with --debug I get this error:

[error_watch] gs-window-x11.c:893 (11:11:28.059): Command output: ** (xfce4-screensaver-dialog:7446): ERROR **: 11:11:28.059: Failed to connect to xfconf daemon: Cannot spawn a message bus when setuid.

OS: Alpine Linux edge (with musl libc), x86_64

$ xfce4-screensaver --version
xfce4-screensaver 4.16.0

Downstream bug report: https://gitlab.alpinelinux.org/alpine/aports/-/issues/13037