ConfigureComponents "Required" preset doesn't work

[spholz]

The install step fails with the following output when selecting the "Required" configuration in ninja -C Build/x86_64 configure-components:

CMake Error at Userland/Libraries/LibWeb/cmake_install.cmake:49 (file):
  file INSTALL cannot find
  "/home/s/repos/serenity/Build/x86_64/Userland/Libraries/LibWeb/CSS/Enums.h":
  No such file or directory.
Call Stack (most recent call first):
  Userland/Libraries/cmake_install.cmake:392 (include)
  Userland/cmake_install.cmake:67 (include)
  cmake_install.cmake:56 (include)