Enable :snippets_vue by default

The commit enables :snippets_vue feature flag by default in both
frontend and backend to slowly introduce this feature to the
self-hosted instances

app/views/projects/snippets/show.html.haml

@@ -3,7 +3,7 @@
 - breadcrumb_title @snippet.to_reference
 - page_title "#{@snippet.title} (#{@snippet.to_reference})", _("Snippets")
 
-- if Feature.enabled?(:snippets_vue)
+- if Feature.enabled?(:snippets_vue, default_enabled: true)
   #js-snippet-view{ data: {'qa-selector': 'snippet_view', 'snippet-gid': @snippet.to_global_id} }
 - else
   = render 'shared/snippets/header'

app/views/snippets/show.html.haml

@@ -4,7 +4,7 @@
 - breadcrumb_title @snippet.to_reference
 - page_title "#{@snippet.title} (#{@snippet.to_reference})", _("Snippets")
 
-- if Feature.enabled?(:snippets_vue)
+- if Feature.enabled?(:snippets_vue, default_enabled: true)
   #js-snippet-view{ data: {'qa-selector': 'snippet_view', 'snippet-gid': @snippet.to_global_id} }
 - else
   = render 'shared/snippets/header'

changelogs/unreleased/207235-snippets-vue-ff-on-by-default.yml

+---
+title: Refactored Snippet view to Vue
+merge_request: 31450
+author:
+type: added

lib/gitlab/gon_helper.rb

@@ -42,7 +42,7 @@ def add_gon_variables
 
       # Initialize gon.features with any flags that should be
       # made globally available to the frontend
-      push_frontend_feature_flag(:snippets_vue, default_enabled: false)
+      push_frontend_feature_flag(:snippets_vue, default_enabled: true)
       push_frontend_feature_flag(:monaco_blobs, default_enabled: false)
       push_frontend_feature_flag(:monaco_ci, default_enabled: false)
       push_frontend_feature_flag(:snippets_edit_vue, default_enabled: false)