fdo#74489 replace '\n' to ' ' in fields (e.g. multiline headings)

Change-Id: I1ce125e459dfcf22adef85efac344ceb320812a2
Reviewed-on: https://gerrit.libreoffice.org/7860
Reviewed-by: Fridrich Strba <fridrich@documentfoundation.org>
Tested-by: Fridrich Strba <fridrich@documentfoundation.org>