Unconditionally export the CCCL path (#14656)

We need to unconditionally export the CCCL path because the condition can no longer be evaluated since the export is happening before the call to `rapids_cpm_cccl` as of #14655. Since cudf should in practice always be getting its own local copy of CCCL, it should be safe to have this export unconditionally; we will never use an externally provided copy of CCCL.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

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

URL: #14656

cpp/cmake/thirdparty/get_cccl.cmake

@@ -31,7 +31,6 @@ function(find_and_configure_cccl)
   rapids_export_find_package_root(
     INSTALL CCCL [=[${CMAKE_CURRENT_LIST_DIR}/../../../include/libcudf/lib/rapids/cmake/cccl]=]
     EXPORT_SET cudf-exports
-    CONDITION CCCL_SOURCE_DIR
   )
 
   # Find or install CCCL with our custom set of patches