applets/battery: adjust show/hide conditions for charge limits
When we are using a charge threshold, the kernel may stop charging within a percentage point of the actual threshold and this is considered correct behavior, so we have to handle that. See https://bugzilla.kernel.org/show_bug.cgi?id=215531.
Also, Upower may give us a status of "Not charging" rather than "Fully charged", so we need to account for that as well. See https://gitlab.freedesktop.org/upower/upower/-/issues/142.
Edited by Nate Graham