fix(plugin-catalog): hermes-lang-vi requires_hermes >=0.21.6, not the unreleased 0.22

The floor named a version that doesn't exist yet, so #134485's requires_hermes
enforcement would refuse the pack on every current release. 0.21.6 is the first
release with the language-pack loader it uses (same floor as hermes-lang-it).

plugin-catalog/hermes-lang-vi.yaml

@@ -5,7 +5,7 @@ description: "Vietnamese (Tieng Viet) language pack for Hermes Agent — full UI
 maintainer: moken627-hub
 tier: community
 category: general
-requires_hermes: '>=0.22'
+requires_hermes: '>=0.21.6'
 docs_url: https://github.com/moken627-hub/hermes-lang-vi#readme
 version: "1.1.1"
 platforms: []