add local-sensitive viewer comparator to data series selection

[mierin12]

Closes #4529

Hello, on some locations there is a case sensitive sorting, on some location not. And more than a case sensitive sorting, I understand it is local sorting for special letter.
I reused what is done in ColumnViewerSorter, f61269a, I understand the goal is to use TextUtil.compare in the different ViewerComparator.

the location where the locale-sensitive sorting is now applied too :

• when selecting data series to plot on graph
• when selecting accounts for creating grouped account and add new accounts to them

Expected behavior :

OK

Before : different behavior elsewhere :

After :