Remove Vale install Make target

What does this Merge Request do?

Since !1510 (merged) was merged, I've seen docs-updating MRs in GDK with failed pipelines:

• !1514 (merged)
• !1515 (closed)
• !1516 (merged)

The "run Vale" make target first checks if Go is installed. Because there is no go binary in the image we use for CI, it instantly fails. We don't need go to run Vale. However, someone would need go to install Vale using the Make target.

For now, we remove the check (and the whole target) to ensure we can move straight on to running Vale.

Merge Request checklist

• Tests added for new functionality. If not, please raise Issue to follow-up.
• This change is backward compatible. If not, please include steps to communicate to our users.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.