Assets model isn't updated when closing and reopening it

The assets model isn't updated when closing a project and reopening it. This causes the assets model to be out of date.

Steps to reproduce.

1. Open a project
2. Add assets
3. Close the project
4. Remove the assets from the file explorer
5. Reopen the project

The assets are still shown because the model wasn't updated, but the actual assets aren't usable anymore.

This is caused due to an optimization in tqtc-qtc-super/qtcreator/src/plugins/qmldesigner/components/assetslibrary/assetslibraryview.cpp:112. When opening, closing, reopen the same project the resourcePath will stay the same.

void AssetsLibraryView::setResourcePath(const QString &resourcePath)
{
    if (resourcePath == m_lastResourcePath)
        return;
    ...
}