chore(ci): drop svace builder images from image ternaries

[nevermarine]

Description

Replace builder/golang-alt-svace-* builder images with builder/golang-alt-1.25
in the SVACE_ENABLED == "false" branch of fromImage ternaries across 16
werf.inc.yaml files. The svace-specific builder images are no longer used; the
standard builder/golang-alt-1.25 image is used instead for both branches.

Why do we need it, and what problem does it solve?

The builder/golang-alt-svace-1.24 / builder/golang-alt-svace-1.25 images are
being dropped from the build pipeline. The svace-enabled builds now use the same
builder/golang-alt-1.25 base as regular builds, so the svace image variants are
no longer needed. This keeps the ternaries referencing an image that actually
exists and builds successfully.

What is the expected result?

1. SVACE_ENABLED builds use builder/golang-alt-1.25 instead of the removed
   builder/golang-alt-svace-* images.
2. Non-svace builds are unaffected (same images as before).
3. All affected images build successfully in CI.

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

[nevermarine]