fix: explicit env var passthrough for sudo on env_reset distros

[SW386]

Problem

On distros with env_reset in sudoers (like we've seen in Ubuntu 26.04 as reported: https://vanta.atlassian.net/browse/PER-10076), sudo -E does not reliably pass through VANTA_KEY, VANTA_OWNER_EMAIL, or VANTA_REGION. The env_reset policy strips the environment regardless of the -E flag, so the dpkg/rpm postinst script never sees the required variables and installation fails silently.

Solution

Replace sudo -E with plain sudo and explicitly forward only the required variables via sudo env VAR=value .... This sidesteps env_reset entirely — the variables are passed as arguments to env rather than inherited through sudo.

VANTA_NOSTART is forwarded conditionally using shell parameter expansion so it is only included when set.

Changes

• install-linux.sh: Replace sudo -E with sudo and pass env vars explicitly to the install command

Fixes PER-10076