Enable Advanced classic group preview

tests/coalition-preview-lobby.test.ts

@@ -56,7 +56,7 @@ void test('group preview refuses incompatible rules and optional alliance settin
   let advanced = apply(lobby(),'at',{type:'coalitionPreview',variant:'three'});
   advanced = apply(advanced,'at',{type:'rules',advanced:true});
   advanced = ready(advanced);
-  assert.throws(() => apply(advanced,'at',{type:'start',advancedPreview:true}), /group|alliance/i);
+  assert.throws(() => apply(advanced,'at',{type:'start'}), /Advanced.*preview/i);
   let shortened = apply(lobby(),'at',{type:'coalitionPreview',variant:'three'});
   shortened = apply(shortened,'at',{type:'shortAllianceVictory',enabled:true});
   shortened = ready(shortened);