MAINT-4481 FIX [viewer-lion] Linux build fails due array-bounds issue in llmanipscale.cpp

This was an out of bounds array access on a code path not normally accessed
To test, set debug setting ScaleShowAxes to true, go into build mode, and hold down Ctrl+Shift to scale an object
There should be colored bars along the scale axes, limited to the bounds of the object's extents