Fix OEP full - spin polarized case

Description

The OEP full was not taking the right occupations for the spin-polarized case.

News snippet

The OEP full was not taking the right occupations for the spin-polarized case.

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.

src/basis_set/orbitalset_inc.F90

@@ -674,7 +674,7 @@ subroutine X(orbitalset_get_position_matrix_elem)(os, ndim, psib, idir, dot)
   SAFE_ALLOCATE(xx(os%sphere%np))
   !$omp parallel do
   do ip = 1, os%sphere%np
-    xx(ip) = os%sphere%rel_x(ip,idir)+os%sphere%center(idir)
+    xx(ip) = os%sphere%rel_x(idir, ip)+os%sphere%center(idir)
   end do
 
   if(psib%status() /= BATCH_DEVICE_PACKED) then