Enables the WebP image format support in Blender. It has been [supported](https://developer.blender.org/rB4fd0a69d7ba) since Blender 3.2 but was disabled due to libwebp missing from the build inputs.
$ nix build nixpkgs#blender
$ nix log (realpath result)
...
-- Could NOT find WebP (missing: _webp_LIBRARIES WEBP_INCLUDE_DIR)
CMake Warning at build_files/cmake/platform/platform_unix.cmake:407 (message):
WebP not found, disabling WITH_IMAGE_WEBP
Call Stack (most recent call first):
CMakeLists.txt:1058 (include)
1f8dd05e72