Use conda mambabuild not mamba mambabuild (#988)

With the release of conda 23.7.3, `mamba mambabuild` stopped working. With boa installed, `conda mambabuild` uses the mamba solver, so just use that instead.

See also rapidsai/cudf#14068.

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

Approvers:
  - Ray Douglass (https://github.com/raydouglass)

URL: #988

ci/build_python.sh

@@ -9,7 +9,7 @@ rapids-print-env
 
 rapids-logger "Begin py build"
 
-rapids-mamba-retry mambabuild \
+rapids-conda-retry mambabuild \
   conda/recipes/ucx-py
 
 rapids-upload-conda-to-s3 python