PTF adds unittest-xml-reporting (#8417)

Co-authored-by: richardyu-ms <richard.yu@microsoft.com>

Author: richardyu-ms

dockers/docker-ptf/Dockerfile.j2

@@ -120,6 +120,7 @@ RUN rm -rf /debs \
     && pip install exabgp==3.4.17\
     && pip install pyaml   \
     && pip install pybrctl pyro4 rpyc yabgp \
+    && pip install unittest-xml-reporting \
     && mkdir -p /opt       \
     && cd /opt             \
     && wget https://raw.githubusercontent.com/p4lang/ptf/master/ptf_nn/ptf_nn_agent.py