Update Docs for Building a Jenkins Container

[ian-jarrett]

https://github.com/Juniper/nita/blob/614d809f273ad70e5f69b14c1330eb464ee6b519/examples/chatgpt/README.md?plain=1#L14C1-L17C1

The Robot Jar file is stored in persistent storage, so updating the binary in the container has no effect at all. Update the docs to describe how to update the version on the NITA host that is mounted in persistent storage by the Jenkins container.

[ian-jarrett]

After investigation, found that the Java options for the "failedCases" Robot plugin needs to be set it jenkins.sh, so this needs to be included in the container build (i.e. Dockerfile) and also chmod to 755 (in the Dockerfile). The Robot Jar file can also be included in the Dockerfile and included in the container, or just as easily can be copied to the correct location under /mnt from the NITA host.