Don't let progress spinners spin by default, and always stop them when done with them (even if hidden)
https://gitlab.gnome.org/GNOME/Incubator/papers/-/blob/main/shell/pps-find-sidebar.ui#L32 sets at least one spinner as spinning by default. There might be other such instances in the code, I haven't looked.
Due to the way GtkSpinner currently works, this will constantly eat CPU, causing heat and power consumption (trust me on that one).
It needs to not spin when not "shown and actively used".
Edited by Jeff Fortin