Router, place via: fix issue created by 45b2bc: cancelling via must be made

only when the select layer is called.
Fixes #7606
https://gitlab.com/kicad/code/kicad/issues/7606

pcbnew/router/router_tool.cpp

@@ -758,12 +758,12 @@ int ROUTER_TOOL::handleLayerSwitch( const TOOL_EVENT& aEvent, bool aForceVia )
 
             // Reset the cursor to the end of the track
             controls()->SetCursorPosition( m_endSnapPoint );
+
+            if( targetLayer == UNDEFINED_LAYER )    // cancelled by user
+                return 0;
         }
     }
 
-    if( targetLayer == UNDEFINED_LAYER )
-        return 0;
-
     // fixme: P&S supports more than one fixed layer pair. Update the dialog?
     sizes.ClearLayerPairs();