fix(test env): ensure build user in environment

[egibs]

The Test pipeline environment does not get a build user included by default; this causes test pipelines to fail when the qemu runner is used because the initial connection attempt to get the host public key always uses the build user to connect. Fix this by adding the build user to all Test environments, both the primary pipeline and any subpipelines.

Fixes: #1732

Melange Pull Request Template

Functional Changes

• This change can build all of Wolfi without errors (describe results in notes)

Notes:

SCA Changes

• Examining several representative APKs show no regression / the desired effect (details in notes)

Notes:

Linter

• The new check is clean across Wolfi
• The new check is opt-in or a warning

Notes: