feat(session): reset failed units before start

Sometimes services can fail. Failed services will generally not be
restarted by systemd. To start previously failed services we can
just reset their failed state before starting our session target.

src/session.sh

@@ -91,6 +91,9 @@ if hash dbus-update-activation-environment 2>/dev/null; then
     dbus-update-activation-environment --systemd ${VARIABLES:- --all}
 fi
 
+# reset failed state of all user units
+systemctl --user reset-failed
+
 # shellcheck disable=SC2086
 systemctl --user import-environment $VARIABLES
 systemctl --user start "$SESSION_TARGET"