cassini-ci: Remove `CI_JOB_ID` folder name

The artifactory upload config contained `CI_JOB_ID` as the target folder
which was causing the test logs not to be deleted. Removed the
`CI_JOB_ID` folder name from upload target config so that JFrog will
automatically delete test logs when number of builds goes beyond 10.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>