Install script fails without sudo due to missing $SUDO prefix in transactional-update commands

[ChrisBeaker]

Environmental Info:
K3s Version:
none, install.sh is affected

Node(s) CPU architecture, OS, and Version:
n/a

Cluster Configuration:
n/a

Describe the bug:
The k3s install script fails when executed as non-root user, because the transactional-update commands do not prefix the $SUDO variable. This causes issues in environments where sudo is required.

Steps To Reproduce:
Run k3s install.sh script as non-root user on systems where transactional-update is needed. (e.g. SUSE Linux Micro 6.0)

  curl -sfL https://get.k3s.io/ | sh -

Expected behavior:
Installation succeeds without issues.

Actual behavior:
Installation fails:

+ transactional-update --no-selfupdate -d run mkdir -p /var/lib/rpm-state
main: line 670: transactional-update: command not found

Additional context / logs:
PR prepared, see below