Revert the accidental addition of python-lxml (#25432)

I inadvertedly added python-lxml to the cloudstack-simulator Dockerfile.

This PR reverts this specific change.

This relates to PR #25324

test/utils/docker/cloudstack-simulator/Dockerfile

@@ -15,7 +15,6 @@ RUN apt-get -y update && apt-get install -y \
     netcat \
     openjdk-8-jdk \
     python-dev \
-    python-lxml \
     python-mysql.connector \
     python-pip \
     python-setuptools \