[CI] Extract Jenkins CLI jar from jenkins.war

INFINIOPS-296

What: Get jenkins-cli.jar from the bundled jenkins.war
instead of downloading it from repo.jenkins-ci.org.
How: Unzip WEB-INF/lib/cli-${JENKINS_VERSION}.jar out of
jenkins.war into /opt/jenkins-cli and clean up /tmp.
Why: The previously working repo.jenkins-ci.org URL now
returns HTTP 403, breaking the Jenkins image build.

Signed-off-by: Benny Itkin <bitkin@nvidia.com>

Author: BennyItkin

.github/Dockerfile.jenkins

@@ -10,7 +10,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends curl python3 py
   && rm -rf /var/lib/apt/lists/* \
   && mkdir -p /opt/jenkins-cli \
   && JENKINS_VERSION=$(/opt/java/openjdk/bin/java -jar /usr/share/jenkins/jenkins.war --version) \
-  && curl -fsSL "https://repo.jenkins-ci.org/public/org/jenkins-ci/main/cli/${JENKINS_VERSION}/cli-${JENKINS_VERSION}.jar" -o /opt/jenkins-cli/jenkins-cli.jar \
+  && unzip /usr/share/jenkins/jenkins.war WEB-INF/lib/cli-${JENKINS_VERSION}.jar -d /tmp \
+  && mv /tmp/WEB-INF/lib/cli-${JENKINS_VERSION}.jar /opt/jenkins-cli/jenkins-cli.jar \
+  && rm -rf /tmp/WEB-INF/ \
   && chmod 0644 /opt/jenkins-cli/jenkins-cli.jar \
   && mkdir -p /opt/docker-bin \
   && arch="${TARGETARCH:-}" \