Description

Improvements to the TDOuput = n_excited_el option:

When we compute the number of electrons not in valence bands of the GS basis, we only need the occupied states.
There is no need to do a reduction for the occ array, as it is shared by all tasks.

News snippet

Improvements to the TDOuput = n_excited_el option.

Checklist

I have checked that my code follows the Octopus coding standards
[] I have added tests for all the new features added in this request.