status/power: Merge with system indicator

Now that the old system menu has been ported over, we can move
the power toggle to its intended place. The main difference to
the stand-alone toggle is that the button now uses its natural
size rather than the fixed size of regular quick items.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2393>

js/js-resources.gresource.xml

@@ -141,7 +141,6 @@
     <file>ui/status/keyboard.js</file>
     <file>ui/status/nightLight.js</file>
     <file>ui/status/network.js</file>
-    <file>ui/status/power.js</file>
     <file>ui/status/powerProfiles.js</file>
     <file>ui/status/rfkill.js</file>
     <file>ui/status/volume.js</file>