prevent invalid ooxml files during notes export, related #i83060#

Change-Id: I151c14cd75477445465e0221271f9bf17385af9f
multiple pivot tables on same sheet OOXML fix (part1), related #i83250#

This just fixes the generation of the pivot table file and the
relationship. It crashed in a dbgutil build because we tried to
overwrite the same stream for each pivot table on one sheet.

Change-Id: If2c9541e38b483ead75fff32d5f6d9e16970e702
fix invalid string access, related #i83611#

Change-Id: I5954f78e10d99a064f83e96282c28c086c7f07f1