fdo#73389 Writer does not show a docx-document with nested table correctly

The table manager can work with more table simultaneously
and so m_aCellWidths contains more table's properties.Only one
item of it belongs to the current table (getCurrentCellwidths).
Regression from 74c5ed19f430327988194cdcd6bdff09591a93fa

Change-Id: I93efac0c004af1b2524c955ffb20c3ecd74a2920