CI: enable optix in linux-plain

Signed-off-by: Vicente Adolfo Bolea Sanchez <vicente.bolea@kitware.com>

.gitlab/ci/configure_linux_plain.cmake

 set(ENABLE_lookingglass ON  CACHE BOOL "")
 set(ENABLE_fides ON CACHE BOOL "")
+set(ENABLE_nvidiaoptix ON CACHE BOOL "")
 
 include("${CMAKE_CURRENT_LIST_DIR}/configure_common.cmake")

.gitlab/ci/configure_windows.cmake

@@ -6,6 +6,7 @@ set(ENABLE_openimagedenoise OFF CACHE BOOL "")
 set(ENABLE_openvr ON CACHE BOOL "")
 set(ENABLE_visrtx ON CACHE BOOL "")
 set(ENABLE_vortexfinder2 OFF CACHE BOOL "")
+set(ENABLE_nvidiaoptix ON CACHE BOOL "")
 
 file(TO_CMAKE_PATH "$ENV{CI_PROJECT_DIR}/.gitlab/qt" cmake_qt_prefix)
 set(CMAKE_PREFIX_PATH "${cmake_qt_prefix}" CACHE STRING "")