docking: Always affect the input region when adding the dock

We need to ensure that input region is affected by the dock even when
it's not in auto-hide mode. In fact before we were not applying this to
the dock actor, but still to the scroll one.

Now we're doing it for the whole group.

Closes: #2032, closes: #2024

LP: #2022885

docking.js

@@ -445,7 +445,6 @@ const DockedDash = GObject.registerClass({
     _trackDock() {
         if (DockManager.settings.dockFixed) {
             Main.layoutManager.addChrome(this, {
-                affectsInputRegion: false,
                 trackFullscreen: true,
                 affectsStruts: true,
             });