Upgrade scapy in the PTF's python3 virtualenv to 2.5.0 (#15573)

This is primarily to fix a bug in scapy hitting an error when trying to
listen on multiple interfaces in a single `sniff` call. This also
upgrades it to the current latest version.

Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>

dockers/docker-ptf/Dockerfile.j2

@@ -174,7 +174,7 @@ RUN python3 -m pip install setuptools \
     && pip3 install itsdangerous \
     && pip3 install retrying \
     && pip3 install jinja2 \
-    && pip3 install scapy==2.4.5 \
+    && pip3 install scapy==2.5.0 \
     && pip3 install thrift
 
 {% if docker_ptf_whls.strip() -%}