Remove CCCL::Thrust from GLOBAL_TARGETS. (#500)

I saw an error (below) and @robertmaynard helped me identify that this change was needed.

I was building cuGraph ([this branch](rapidsai/cugraph#4052)) with rapids-cmake pointing to [this branch](NVIDIA/cuCollections#404) of cuCollections.
```
-- CPM: Adding package [email protected] (cccl-2.2.0)
CMake Error at build/release/_deps/rapids-cmake-src/rapids-cmake/cmake/make_global.cmake:59 (set_target_properties):
  Attempt to promote imported target "CCCL::Thrust" to global scope (by
  setting IMPORTED_GLOBAL) which is not built in this directory.
Call Stack (most recent call first):
  build/release/_deps/rapids-cmake-src/rapids-cmake/cpm/find.cmake:189 (rapids_cmake_make_global)
  build/release/_deps/rapids-cmake-src/rapids-cmake/cpm/cccl.cmake:85 (rapids_cpm_find)
  build/release/_deps/cuco-src/cmake/thirdparty/get_cccl.cmake:18 (rapids_cpm_cccl)
  build/release/_deps/cuco-src/cmake/thirdparty/get_cccl.cmake:21 (find_and_configure_cccl)
  build/release/_deps/cuco-src/CMakeLists.txt:79 (include)
```

Authors:
  - Bradley Dice (https://github.com/bdice)

Approvers:
  - Robert Maynard (https://github.com/robertmaynard)

URL: #500

rapids-cmake/cpm/cccl.cmake

@@ -83,7 +83,7 @@ function(rapids_cpm_cccl)
 
   include("${rapids-cmake-dir}/cpm/find.cmake")
   rapids_cpm_find(CCCL ${version} ${ARGN}
-                  GLOBAL_TARGETS CCCL CCCL::CCCL CCCL::Thrust CCCL::CUB CCCL::libcudacxx
+                  GLOBAL_TARGETS CCCL CCCL::CCCL CCCL::CUB CCCL::libcudacxx
                   CPM_ARGS FIND_PACKAGE_ARGUMENTS EXACT
                   GIT_REPOSITORY ${repository}
                   GIT_TAG ${tag}