Simplify torchdata version extraction in packaging script (#2129)

* Simplify torchdata extraction

* fix regex

Author: atalman

packaging/install_torchdata.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 package_type="$PACKAGE_TYPE"
-channel="$CHANNEl"
+channel="$CHANNEL"
 if [ -z "$package_type" ]; then
   package_type="wheel"
 fi
@@ -33,14 +33,7 @@ $install_cmd torchdata $install_channel
 if [ "$package_type" = "wheel" ]; then
   TORCHDATA_VERSION="$(pip show torchdata | grep ^Version: | sed 's/Version:  *//' | sed 's/+.\+//')"
 else
-  TORCHDATA_VERSION="$(conda search --json 'torchdata[channel=pytorch-'"${channel}"] | \
-    python -c "import json, os, re, sys; \
-      cuver = 'cpu'; \
-      pyver = os.environ.get('PYTHON_VERSION').replace('.', ''); \
-      print(re.sub(r'\\+.*$', '',
-        [x['version'] for x in json.load(sys.stdin)['torchdata'] \
-          if 'py' + pyver in x['fn']][-1]))"
-      )"
+  TORCHDATA_VERSION="$(conda list -fe torchdata | grep torchdata | sed -e 's/torchdata=\(.*\)=py.*/\1/')"
   echo "export CONDA_TORCHDATA_CONSTRAINT='- torchdata==${TORCHDATA_VERSION}'" >> "${BUILD_ENV_FILE}"
 fi