Don't toggle when state is TRISTATE_INDET

Removing the toggle() from SetState() allows to programmatically
set a TRISTATE_INDET

Required for a4341164a1

Change-Id: Id016a0ec6846529873f41e02be1a48a42d88be42
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/199233
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <heiko.tietze@documentfoundation.org>

vcl/source/control/button.cxx

@@ -3578,7 +3578,8 @@ void CheckBox::SetState( TriState eState )
     {
         meState = eState;
         StateChanged( StateChangedType::State );
-        Toggle();
+        if (eState != TRISTATE_INDET) // just removing Toggle() fails at the ui test /tdf65334.py
+            Toggle();
     }
 }