fix odf validation errors around new chart regression curves

Change-Id: If67207abb204b5aca8365737088437b12ac6eaf1
fix one more ODF validation error

Change-Id: I265ea970043a954e2e60234d4b3ff90956c939ec
add export validation tests for chart2

ODS and DOCX are still disabled

Change-Id: I2ce30df5fe8977c83a77ca210d79530423bef76e