starmath: directly create utf8 OUString
starmath: directly create utf8 OUString

This fixes:

warn:rtl.string:14867:1:sal/rtl/strtmpl.cxx:1269: rtl_uString_newFromLiteral - Found char > 127

Change-Id: I1f868406501c83918fc3c06dd0b68eb1f6604f26

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core