Do not require `VecTraits` for `UnknownArrayHandle` components
Whan an UnknownArrayHandler
is constructed from an ArrayHandle
, it uses
the VecTraits
of the component type to construct its internal functions.
This meant that you could not put an ArrayHandle
with a component type
that did not have VecTraits
into an UnknownArrayHandle
.
UnknownArrayHandle
now no longer needs the components of its arrays to
have VecTraits
. If the component type of the array does not have
VecTraits
, it treats the components as if they are a scalar type.