config change after VtsPythonVirtualenvPreparer change

VtsPythonVirtualenvPreparer was both a target preparer and multi target preparer.
The new TF suite requires it to be only one of them.
This CL configs vts xmls to use VtsPythonVirtualenvPreparer as multi target preparer

Test: vts-selftest
Bug: 69307585
Change-Id: I3a4de4bbfefcfdf70ffd5aa9609da9e74b38e3c3
Merged-In: I3a4de4bbfefcfdf70ffd5aa9609da9e74b38e3c3
diff --git a/test/hidl_test/AndroidTest.xml b/test/hidl_test/AndroidTest.xml
index 1490078..6633942 100644
--- a/test/hidl_test/AndroidTest.xml
+++ b/test/hidl_test/AndroidTest.xml
@@ -24,7 +24,7 @@
         <option name="push" value="DATA/nativetest64/hidl_test_client/hidl_test_client->/data/nativetest64/hidl_test_client/hidl_test_client" />
         <option name="push" value="DATA/nativetest64/hidl_test_helper->/data/nativetest64/hidl_test_helper" />
     </target_preparer>
-    <target_preparer class="com.android.tradefed.targetprep.VtsPythonVirtualenvPreparer" />
+    <multi_target_preparer class="com.android.tradefed.targetprep.VtsPythonVirtualenvPreparer" />
     <test class="com.android.tradefed.testtype.VtsMultiDeviceTest">
       <option name="test-module-name" value="VtsHidlUnitTests" />
       <option name="binary-test-type" value="binary_test" />