Update install_all_python_modules.sh to account for new packages (#31103)

* Update install_all_python_modules.sh to account for new packages

* Improve readability

tools/distrib/install_all_python_modules.sh

@@ -13,13 +13,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# TODO: Integrate this into CI to avoid bitrot.
+
 echo "It's recommended that you run this script from a virtual environment."
 
+function maybe_run_command () {
+  if python setup.py --help-commands | grep "$1" &>/dev/null; then
+    python setup.py "$1";
+  fi
+}
+
 set -e
 
 BASEDIR=$(dirname "$0")
 BASEDIR=$(realpath "$BASEDIR")/../..
 
+PACKAGES="grpcio_channelz  grpcio_csds  grpcio_admin grpcio_health_checking  grpcio_reflection  grpcio_status  grpcio_testing  grpcio_tests"
+
 (cd "$BASEDIR";
   pip install --upgrade cython;
   python setup.py install;
@@ -28,9 +38,11 @@ BASEDIR=$(realpath "$BASEDIR")/../..
     GRPC_PYTHON_BUILD_WITH_CYTHON=1 pip install .
   popd;
   pushd src/python;
-    for PACKAGE in ./grpcio_*; do
+    for PACKAGE in ${PACKAGES}; do
       pushd "${PACKAGE}";
-        python setup.py preprocess;
+        python setup.py clean;
+        maybe_run_command preprocess
+        maybe_run_command build_package_protos
         python setup.py install;
       popd;
     done