Update kvikio call due to upstream changes (#17733)

KvikIO has just introduced slightly breaking code changes (rapidsai/kvikio#581) where the utility function `getenv_or` is moved out of the `detail` namespace and becomes part of the public API. This PR adapts cuDF for this change.

This PR has been tested locally using the abovementioned KvikIO branch.

Authors:
  - Tianyu Liu (https://github.com/kingcrimsontianyu)
  - GALI PREM SAGAR (https://github.com/galipremsagar)

Approvers:
  - Devavret Makkar (https://github.com/devavret)
  - Bradley Dice (https://github.com/bdice)
  - Muhammad Haseeb (https://github.com/mhaseeb123)

URL: #17733

cpp/src/io/utilities/config_utils.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -56,8 +56,7 @@ void set_up_kvikio()
 {
   static std::once_flag flag{};
   std::call_once(flag, [] {
-    auto const compat_mode =
-      kvikio::detail::getenv_or("KVIKIO_COMPAT_MODE", kvikio::CompatMode::ON);
+    auto const compat_mode = kvikio::getenv_or("KVIKIO_COMPAT_MODE", kvikio::CompatMode::ON);
     kvikio::defaults::compat_mode_reset(compat_mode);
 
     auto const nthreads = getenv_or<unsigned int>("KVIKIO_NTHREADS", 4u);