[OPENJDK-3645] Remove jmods rpm installation from stage 1

[Josh-Matsuoka]

Fixes https://issues.redhat.com/browse/OPENJDK-3645

Removes the installation of the jmods rpm from stage 1 of the jlink build. Since it's already installed in the tech-preview image it's no longer needed here and can be safely removed.

To test:

• Build the tech preview image

cekit --descriptor ubi9-openjdk-21.yaml build podman

• Set up a new Openshift Project

oc new-project jlink-dev
oc project jlink-dev
oc create imagestream openjdk-21-jlink-tech-preview

• Push the tech preview images to the created imagestream

podman tag openjdk-tech-preview/openjdk-21-jlink-rhel9:latest default-route-openshift-image-registry.apps-crc.testing/jlink-dev/openjdk-21-jlink-tech-preview:latest
        podman push default-route-openshift-image-registry.apps-crc.testing/jlink-dev/openjdk-21-jlink-tech-preview:latest

• Run the template and observe the builds

oc create -f templates/jlink/jlinked-app.yaml
oc process -n jlink -f templates/jlink/jlinked-app.yaml -p APP_URI=https://github.com/jboss-container-images/openjdk-test-applications -p JDK_VERSION=21 -p REF=master -p CONTEXT_DIR=quarkus-quickstarts/getting-started-3.9.2-uberjar -p TARGET_PORT=8080 -p SERVICE_PORT=8080 -p APPNAME=quarkus-3645 | oc create -f -

• Check the logs of quarkus-3645-jlink-builder-jdk-21-1, the jmods rpm should not be pulled in.

[sefroberg]

Code looks fine. We need to stabilize the behave tests.