[cli] esc env rm without arguments unexpectedly deletes entire environment

[fnune]

The esc env rm <env> command without additional positional arguments deletes the entire environment, which is unexpected and potentially dangerous.

Normally, esc env rm is used to remove data from an environment using positional arguments. The current behavior where omitting those arguments results in full environment deletion is confusing and has led to accidental deletions.

This behavior contributed to the need for environment deletion protection features.

Context: https://pulumi.slack.com/archives/C04UZTMV0TF/p1730754600752399