environment: Preserve time 0 when animations are disabled

environment: Preserve time 0 when animations are disabled

There are cases where the animation time is set to 0 on purpose
in order to not animate. When animations are disabled via
/org/gnome/desktop/interface/enable-animations those animation
times are increased from 0 to 1. This makes the "Caps lock is on."
message appear unconditionally in the lockscreen for a brief moment.

Select the minimum between the two values. So that an animation time
0 is preserved instead of being replaced by 1.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2471>