In #378 we merged supported for the new 7.10 'install' subcommand. This changed the existing tests, which is ok (they were failing) but they were valid and needed tests.

The remaining tasks are

1. to decide if we want to start a separate file for any remaining 'subcommands' as we had discussed here:
   [Fleet / Agent ] support install / uninstall command from Agent #326

• tl;dr; the remaining ones are 'help' 'inspect' 'version' (and as of 7.10 'upgrade' and 'enroll' which was orphaned when we changed for the 'install' as noted above)

2. to add in the .deb and .rpm syntax to the installer tests where desired, to maintain the coverage we had, using 'enroll' and 'run' subcommands as prior, which is still valid (tho is failing in recent builds and hopefully soon fixed).

• the changes will go in
  https://github.com/elastic/e2e-testing/blob/master/e2e/_suites/fleet/features/fleet_mode_agent.feature
• and should be fairly easy to add, as in just duplicating the 2 rows and changing the installer type.

the .deb/.rpm issue logged for Beats is:
elastic/beats#21200

after that, we encountered and have since fixed this as well that relates:
elastic/beats#22485