Ensure pytest is run from relevant directories in GH Actions (#5101)

This PR undoes some erroneous changes I made in #5075.

According to @bdice, it's necessary to `cd` into the relevant directories when running `pytest` to avoid issues with `codecov`.

Authors:
  - AJ Schmidt (https://github.com/ajschmidt8)

Approvers:
  - Sevag H (https://github.com/sevagh)
  - Bradley Dice (https://github.com/bdice)

URL: #5101

ci/test_python_dask.sh

@@ -5,11 +5,12 @@
 source "$(dirname "$0")/test_python_common.sh"
 
 rapids-logger "pytest cuml-dask"
+cd python/cuml/tests/dask
 pytest \
   --cache-clear \
   --junitxml="${RAPIDS_TESTS_DIR}/junit-cuml-dask.xml" \
-  --cov-config=python/.coveragerc \
+  --cov-config=../../../.coveragerc \
   --cov=cuml_dask \
   --cov-report=xml:"${RAPIDS_COVERAGE_DIR}/cuml-dask-coverage.xml" \
   --cov-report=term \
-  python/cuml/tests/dask
+  .

ci/test_python_singlegpu.sh

@@ -5,13 +5,14 @@
 source "$(dirname "$0")/test_python_common.sh"
 
 rapids-logger "pytest cuml single GPU"
+cd python/cuml/tests
 pytest \
   --numprocesses=8 \
-  --ignore=python/cuml/tests/dask \
+  --ignore=dask \
   --cache-clear \
   --junitxml="${RAPIDS_TESTS_DIR}/junit-cuml.xml" \
-  --cov-config=python/.coveragerc \
+  --cov-config=../../.coveragerc \
   --cov=cuml \
   --cov-report=xml:"${RAPIDS_COVERAGE_DIR}/cuml-coverage.xml" \
   --cov-report=term \
-  python/cuml/tests
+  .