Protect VIEW against oddball items

Importing may have more view layers than we allocate.  In these cases,
we need to avoid accidentally writing to unallocated view layers

Fixes https://gitlab.com/kicad/code/kicad/issues/13638

common/view/view.cpp

@@ -333,6 +333,9 @@ void VIEW::Add( VIEW_ITEM* aItem, int aDrawPriority )
 
     for( int i = 0; i < layers_count; ++i )
     {
+        if( layers[i] < 0 || layers[i] >= m_layers.size() )
+            continue;
+
         VIEW_LAYER& l = m_layers[layers[i]];
         l.items->Insert( aItem );
         MarkTargetDirty( l.target );