XD-1759: Status on shell prompt is inconsistent

Switch back to a SHL snapshot so that
https://github.com/spring-projects/spring-shell/commit/8fa5688ae0ece753437a7f3bb8e278e3d31e6294
gets picked up.
XD-1804: Remove 'substream' support
Remove unused classes
XD-1772: Force use of disambiguating label

Add a test with only one label

label falls back to name if not explicit