fix: clarify validate konnect behaviors

[johnharris85]

Few quick fixes around Konnect behavior:

• The help description for gateway validate vs file validate was incorrect (said both would contact a running CP to validate, file validate does not do this, gateway validate does).
• Message about the konnect section being missing has been changed to a warning (as you can specify konnect cli flags still, and it now returns a 0 exit code for automation purposes) and the message has been clarified.
• --konnect-compatibility and --parallelism flags gated to their relevant parent commands (file validate and gateway validate respectively).

[Prashansa-K]

@johnharris85 Could you please check why the tests are not running for this particular PR?