Clear edited point when exiting tool

When leaving the main point editor loop, we need to ensure that the edit
point is cleared as well.  This is usually cleared by a ClearEvent call
but in case this is missed, we need to ensure that other tools are not
caught out

Fixes https://gitlab.com/kicad/code/kicad/issues/10288

eeschema/tools/ee_point_editor.cpp

@@ -385,6 +385,7 @@ int EE_POINT_EDITOR::Main( const TOOL_EVENT& aEvent )
 
     controls->SetAutoPan( false );
     controls->CaptureCursor( false );
+    setEditedPoint( nullptr );
 
     if( m_editPoints )
     {