pcbnew: Set graphic line width based on layer

Get the board settings when changing the drawing layer.  These include
default line thickness that should be updated.

Fixes: lp:1796489
* https://bugs.launchpad.net/kicad/+bug/1796489

pcbnew/tools/drawing_tool.cpp

@@ -1064,7 +1064,9 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
         }
         else if( evt->IsAction( &PCB_ACTIONS::layerChanged ) )
         {
+            m_lineWidth = getSegmentWidth( getDrawingLayer() );
             aGraphic->SetLayer( getDrawingLayer() );
+            aGraphic->SetWidth( m_lineWidth );
             m_view->Update( &preview );
             frame()->SetMsgPanel( aGraphic );
         }
@@ -1266,6 +1268,14 @@ bool DRAWING_TOOL::drawArc( DRAWSEGMENT*& aGraphic )
             aGraphic = nullptr;
             break;
         }
+        else if( evt->IsAction( &PCB_ACTIONS::layerChanged ) )
+        {
+            m_lineWidth = getSegmentWidth( getDrawingLayer() );
+            aGraphic->SetLayer( getDrawingLayer() );
+            aGraphic->SetWidth( m_lineWidth );
+            m_view->Update( &preview );
+            frame()->SetMsgPanel( aGraphic );
+        }
         else if( evt->IsClick( BUT_RIGHT ) )
         {
             m_menu.ShowContextMenu();