fdo#53920 Switch back tab at RefButton closure time

Bug occurs because visible tab is not the initial tab. So, instead of
switching back to initial tab at dialog closure time (removed from
cellsh2.cxx), this commit proposes that switching back to initial tab
is operate when expanding the RefButton shrink dialog.

Change-Id: I3cf7ed14054fa69881d4ecbc55c48dfbfc4356aa
Reviewed-on: https://gerrit.libreoffice.org/11660
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>
Tested-by: Kohei Yoshida <libreoffice@kohei.us>