CLI - Config-modifying commands print the "saving config" text twice

[bfops]

Background

Commands like spacetime server set-default print the "Saving config" text twice.

This is because all commands save the config once right after loading it. (So this issue likely applies to all commands that actually modify the config).

Definition of Done

• Stop saving the config unconditionally; only save when we actually make changes
  • including if the file wasn't found