FIX: Admin sidebar problem check missing -1 check (#30916)

When we initially turned on admin sidebar for new sites,
existing sites had the value set to -1. We need to show
the problem check to these sites too, but currently it only
checks if `admin_sidebar_enabled_groups` is empty.

app/services/problem_check/admin_sidebar_deprecation.rb

@@ -4,7 +4,10 @@ class ProblemCheck::AdminSidebarDeprecation < ProblemCheck::ProblemCheck
   self.priority = "low"
 
   def call
-    return no_problem if SiteSetting.admin_sidebar_enabled_groups.present?
+    if SiteSetting.admin_sidebar_enabled_groups.present? &&
+         SiteSetting.admin_sidebar_enabled_groups != "-1"
+      return no_problem
+    end
 
     problem
   end

config/locales/server.en.yml

@@ -1724,7 +1724,7 @@ en:
       google_analytics_version: "Your Discourse is currently using Google Analytics 3, which will no longer be supported after July 2023. <a href='https://meta.discourse.org/t/260498'>Upgrade to Google Analytics 4</a> now to continue receiving valuable insights and analytics for your website's performance."
       category_style_deprecated: "Your Discourse is currently using a deprecated category style which will be removed before the final beta release of Discourse 3.2. Please refer to <a href='https://meta.discourse.org/t/282441'>Moving to a Single Category Style Site Setting</a> for instructions on how to keep your selected category style."
       maxmind_db_configuration: 'The server has been configured to use MaxMind databases for reverse IP lookups but a valid MaxMind account ID has not been configured which may result in MaxMind databases failing to download in the future. <a href="https://meta.discourse.org/t/configure-maxmind-for-reverse-ip-lookups/173941" target="_blank">See this guide to learn more</a>.'
-      admin_sidebar_deprecation: "The old admin layout is deprecated in favour of the new <a href='https://meta.discourse.org/t/introducing-experimental-admin-sidebar-navigation/289281'>sidebar layout</a> and will be removed in the next release. You can <a href='%{base_path}/admin/config/navigation?filter=admin%20sidebar'>configure</a> the new sidebar layout now to opt in before that."
+      admin_sidebar_deprecation: "The old admin layout is deprecated in favour of the new <a href='https://meta.discourse.org/t/-/289281'>sidebar layout</a> and will be removed in the next release. You can <a href='%{base_path}/admin/config/navigation?filter=admin%20sidebar'>configure</a> the new sidebar layout now to opt in before that."
     back_from_logster_text: "Back to site"
 
   site_settings:

spec/services/problem_check/admin_sidebar_deprecation_spec.rb

@@ -17,7 +17,17 @@ RSpec.describe ProblemCheck::AdminSidebarDeprecation do
 
       it do
         expect(check).to have_a_problem.with_priority("low").with_message(
-          "The old admin layout is deprecated in favour of the new <a href='https://meta.discourse.org/t/introducing-experimental-admin-sidebar-navigation/289281'>sidebar layout</a> and will be removed in the next release. You can <a href='/admin/config/navigation?filter=admin%20sidebar'>configure</a> the new sidebar layout now to opt in before that.",
+          "The old admin layout is deprecated in favour of the new <a href='https://meta.discourse.org/t/-/289281'>sidebar layout</a> and will be removed in the next release. You can <a href='/admin/config/navigation?filter=admin%20sidebar'>configure</a> the new sidebar layout now to opt in before that.",
+        )
+      end
+    end
+
+    context "when sidebar is set to -1 from the initial migration" do
+      let(:configured) { "-1" }
+
+      it do
+        expect(check).to have_a_problem.with_priority("low").with_message(
+          "The old admin layout is deprecated in favour of the new <a href='https://meta.discourse.org/t/-/289281'>sidebar layout</a> and will be removed in the next release. You can <a href='/admin/config/navigation?filter=admin%20sidebar'>configure</a> the new sidebar layout now to opt in before that.",
         )
       end
     end