Search for Effects cannot be done when Materials and Textures are not downloadable

This can happen if user doesn't have internet connection. Also an issue on Linux Ubuntu20.04 where downloads fail (https://bugreports.qt.io/browse/QDS-10005). Steps to reproduce:

• Make sure you don't have internet connection
• Delete QtDesignStudio folder in C:\Users\<user>\Documents
• Open Design Studio and create a project
• ->In Content Library, search is disabled completely. Would expect it to work for Effects even though other assets cannot be used.