ci: Collapse disk usage in after_script

What does this MR do and why?

The extra logging is annoying and force to scroll up to see test results. I kept the disk usage logging expanded in the before_script because for this one you have to scroll up anyway and it's the most useful to see if a runner is out of disk space before even starting to run any tests. The logging in after_script is more a FYI type of logging.

Screenshots

before_script	after_script