Remove cumlprims from clang-format (#7647)

Minor cleanup of clang-format settings now that cumlprims has been integrated into cuml.

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

Approvers:
  - Anupam (https://github.com/aamijar)
  - Jim Crist-Harif (https://github.com/jcrist)

URL: #7647

Author: bdice

cpp/.clang-format

@@ -79,7 +79,7 @@ IncludeCategories:
     Priority:        2
   - Regex:           '^<cuml/' # cuML includes
     Priority:        3
-  - Regex:           '^<(cudf|raft|kvikio|cumlprims)' # Other RAPIDS includes
+  - Regex:           '^<(cudf|raft|kvikio)' # Other RAPIDS includes
     Priority:        4
   - Regex:           '^<rmm/' # RMM includes
     Priority:        5