Improve error message when a data node is active in the previous period and there is a cashflow import for the next period

[dtrzesniak]

Problem is here in the import storage:
// if(allImportScopesNotAtInceptionYear.Any()) {

the error give is generic: Sequence contains no elements

the error should be something like: you are trying to import data for a data node that was active in the previous period, but has no data (i.e the previous partition has not be created, thus the .Single() within the code is empty).

to reproduce, go to Interact With Import Scope Calculation and try to import a cf for a future year (say 2023) to any of the active data nodes we have (without having the previous 2024 year, of course)