fix python throughput test

Author: Elliot Kim

test-vine-task-throughput.sh

@@ -4,10 +4,7 @@
 . ./install-conda-devel.sh
 
 # Install conda development environment
-source ./install-github.sh
-
-conda create -yq --prefix ${CONDA_ENV} -c conda-forge --strict-channel-priority ndcctools dask
-conda activate ${CONDA_ENV}
+. ./install-github.sh
 
 # Run the test case.
 python3 test-vine-task-throughput.py