Should save a lot of debugging of out-of-sync part state between
the calc core and lok clients.

at   ScTabControl::Select ()
from ScTabControl::SwitchToPageId (... nId=2)
from doc_setPart (... nPart=1)

we really don't want to hit this:

   if ( pScMod->IsTableLocked() )      // may not be switched now ?
   {                                                                                                                                │
       // restore the old state of TabControls

Change-Id: I02b29e9e0e29ce37b64e3f082811bc080c0dc254
Reviewed-on: https://gerrit.libreoffice.org/72114
Tested-by: Jenkins
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>