* Make all call interfaces in etl::delegate conditionally noexcept
This covers the case when the invoked code can throw.
For operator(), this was already implemented. Do similarly for the
other call interfaces.
* Make all call interfaces in etl::closure conditionally noexcept
Similar to etl::delegate, the contained delegate might be
throwing. Apply the same solution as in etl::delegate to make
the call interfaces conditionally noexcept.
