Add pytest-stress to sonic-mgmt image (#21304)

Why I did it
Adding pytest-stress to sonic-mgmt image will help in running stress tests.

How I did it
pip install pytest-stress plugin

How to verify it
Manually tested the image with DUT

Tested branch (Please provide the tested image version)
Not applicable.

Description for the changelog
Adding pytest-stress to sonic-mgmt image will help in running stress tests.

Link to config_db schema for YANG module changes
Not applicable

dockers/docker-sonic-mgmt/Dockerfile.j2

@@ -92,6 +92,7 @@ RUN python3 -m pip install aiohttp \
                  pytest-xdist==1.28.0 \
                  python-dateutil \
                  pytest==7.4.0 \
+                 pytest-stress \
                  PyYAML \
                  redis \
                  requests \
@@ -175,6 +176,7 @@ RUN python2 -m pip install allure-pytest==2.8.22 \
                 pytest-repeat \
                 pytest-html \
                 pytest-xdist==1.28.0 \
+                pytest-stress \
                 python-dateutil \
                 PyYAML \
                 redis \