[Bug] Incomplete commands are sent to the backend server

[JasonHorkles]

Bug Description:

What is not working as it should?

When typing an incomplete command, such as /whisper or /carbon with no other args, it sends the command to the backend server. This can cause the player to think the command actually isn't allowed or valid at all.

Steps to reproduce:

1. Install Carbon on Velocity
2. Run a command that requires arguments, such as /whisper, without providing anything else
3. See that the command is sent to the backend server

System Details:

1. Server Type: Velocity
2. Server Software: Velocity 3.4.0-SNAPSHOT (git-f986eb51-b472)
3. MC Version: 1.21.4
4. Carbon Version: 3.0.0-beta.28

Pastebins:

https://pastes.dev/SRXOwc4e0G

Any other relevant details:

Ideally, this should send an error/usage message rather than passing it on. This happens for both the command and its aliases