Set the data label separator to "new line" if there is not
present explicit point separator and the "percentage format
wins over number value format". In MS-Office (2007/2010/2013/2016)
the defult separator is the "new line" in that case, any other
case the separator is a semicolon.

Change-Id: I7f562d814b74eba15b2fba2954efd42747dd7960
Reviewed-on: https://gerrit.libreoffice.org/67974
Tested-by: Jenkins
Reviewed-by: László Németh <nemeth@numbertext.org>