Made attribute block update when switching sprite

If the sprite you switch to doesn’t have an attribute or variable, it
will set the attribute to the default one for sprites or the stage.
Shortened the code a little
Changed "allowed" to "valid"

I think it makes a little more sense.
Use translated default values
Revert "Use translated default values"

This reverts commit 0c7de21dc3b1092d055b9bf294280a64431f856b.
Moved attribute arrays into constants in scratch.BlockMenus
Merge branch 'djdolphin-validate-attributes'