Clarify version removal behavior in EP v2 versioned docs

The previous text implied deleting a branch removes the version from
the customer dropdown. In practice, the dropdown is driven by releases
on the channel, not branches. Deleting the branch removes the exact
content match, but the version still appears and resolves via the
fallback chain. Updated to explain both sides.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AmberAlston

docs/vendor/enterprise-portal-v2-versioned-docs.mdx

@@ -92,7 +92,9 @@ When a customer switches versions via the dropdown, the portal swaps the version
 
 ## Removing versions
 
-To unpublish a version from the dropdown, delete the branch. The version disappears after the next sync.
+To remove a version's dedicated content branch, delete the branch from your git repo. The branch disappears from the Content tab after the next sync.
+
+However, if a release with that version label still exists on a customer's channel, the version still appears in the customer's version dropdown. The portal resolves it using the version resolution chain (nearest lower semver branch, then `main` as fallback). To fully remove a version from the customer's dropdown, the release must also be removed from the channel.
 
 ## Overrides