qmljs: convert QStringView -> QString in +=

+= using QStringView is available only in newer Qt

Change-Id: I67e1cbbfcba07cca826ee4353d0cac08bf46defe
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/qmljs/qmljsbind.cpp

@@ -341,7 +341,7 @@ bool Bind::visit(UiInlineComponent *ast)
         _diagnosticMessages->append(
             errorMessage(ast, tr("Nested inline components are not supported")));
     }
-    _currentComponentName += ast->name;
+    _currentComponentName += ast->name.toString();
     _rootObjectValue = nullptr;
     return true;
 }