Locked pads are a bit different from other locked items
and there are sufficient reasons to need to select them
that it makes sense to introduce this inconsistency.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/6837
CHANGED: Ctrl-middle mouse button double click should perform
'Zoom to Objects' in Pcbnew, but a change in modifier key handling
broke it. This MR restores the functionality.
Fixes https://gitlab.com/kicad/code/kicad/issues/6740