fdo#66969: Set selected page name after building all dimension members.

Because the new implementation relies on the visiblity flag of the
dimension members, they need to exist before setting currently selected
page, which is still used in documents generated by the older version of
LibreOffice.

Change-Id: I6cec5fd3d2165f714fc01b596d3761890d87a4ff
fdo#66969: Reset group dimension data from all referencing pivot objects.

The previous code was doing it only with the first referencing pivot table,
which would break the rest of them sharing the same cache if
the first one doesn't contain all group dimensions used in all of the
referencing pivot tables.

Change-Id: I35d6907ef8db7ed69db42583cac92b2b74406e2c