You are correct that the build errors are due to the missing libuvc_ros package. This is because the package has not bed released for ROS Noetic. However, libuvc_ros is mostly just a wrapper package around the libuvc library, which is available in Ubuntu. Try the following:
1. Install libuvc-dev with apt.
2. Clone https://github.com/ros-drivers/libuvc_ros into your workspace's src folder, along side the Astra driver.
3. Build the workspace with just catkin_make (which will build all packages in the workspace).
If this works, consider contacting the maintainer of libuvc_ros on Github and asking them to release the package for Noetic.