Restore layer variables from QML

Fix #14452

Author: m-kuhn

src/core/qgsvectorlayer.cpp

@@ -1994,6 +1994,8 @@ bool QgsVectorLayer::readSymbology( const QDomNode& node, QString& errorMessage
 
   mConditionalStyles->readXml( node );
 
+  readCustomProperties( node );
+
   return true;
 }