Disable ARM CI in C++ and Python test CI jobs (#18175)

xref rapidsai/shared-workflows#293

Authors:
  - Matthew Murray (https://github.com/Matt711)

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

URL: #18175

.github/workflows/pr.yaml

@@ -153,7 +153,7 @@ jobs:
   conda-cpp-tests:
     needs: [conda-cpp-build, changed-files]
     secrets: inherit
-    uses: rapidsai/shared-workflows/.github/workflows/conda-cpp-tests.yaml@branch-25.04
+    uses: rapidsai/shared-workflows/.github/workflows/conda-cpp-tests.yaml@disable-arm-pr-ci
     if: fromJSON(needs.changed-files.outputs.changed_file_groups).test_cpp
     with:
       build_type: pull-request
@@ -166,7 +166,7 @@ jobs:
   conda-python-cudf-tests:
     needs: [conda-python-build, changed-files]
     secrets: inherit
-    uses: rapidsai/shared-workflows/.github/workflows/conda-python-tests.yaml@branch-25.04
+    uses: rapidsai/shared-workflows/.github/workflows/conda-python-tests.yaml@disable-arm-pr-ci
     if: fromJSON(needs.changed-files.outputs.changed_file_groups).test_python
     with:
       build_type: pull-request