Update Jenkins file to include JUnit Plugin-in tests during build stage

[enriozuni]

With the fixing of issue #427, the JUnit Plugin-in tests will be able to run from the CLI. For this reason, the Jenkins file needs to be changed so that it includes these tests during the build stage in the CI. The command needs to be updated from 'mvn clean package -X -e to 'mvn clean install.

[svenfeld]

Can be closed as tests are now done by the Github Actions CI.