DEV: Don’t provide an array to site settings group lists in specs

This is extracted from https://github.com/discourse/discourse/pull/29129.

In some chat specs, we provide an array as a value for group lists like
`chat_allowed_groups`, which is wrong. This results in a value like
`"1|2|[3]"` instead of `"1|2|3"`.

plugins/chat/spec/requests/chat/api/channels_messages_flags_controller_spec.rb

@@ -9,7 +9,7 @@ RSpec.describe Chat::Api::ChannelsMessagesFlagsController do
   before do
     SiteSetting.chat_enabled = true
     SiteSetting.chat_allowed_groups = Group::AUTO_GROUPS[:everyone]
-    SiteSetting.chat_message_flag_allowed_groups = [Group::AUTO_GROUPS[:everyone]]
+    SiteSetting.chat_message_flag_allowed_groups = Group::AUTO_GROUPS[:everyone]
     sign_in(current_user)
   end
 

plugins/chat/spec/requests/core_ext/bookmarks_controller_spec.rb

@@ -8,7 +8,7 @@ RSpec.describe BookmarksController do
 
   before do
     register_test_bookmarkable(Chat::MessageBookmarkable)
-    SiteSetting.chat_allowed_groups = [chatters]
+    SiteSetting.chat_allowed_groups = chatters
     sign_in(current_user)
   end
 

plugins/chat/spec/requests/core_ext/notifications_controller_spec.rb

@@ -13,7 +13,7 @@ RSpec.describe NotificationsController do
     before do
       Jobs.run_immediately!
       SiteSetting.chat_enabled = true
-      SiteSetting.chat_allowed_groups = [chatters.id]
+      SiteSetting.chat_allowed_groups = chatters.id
       sign_in(user)
     end
 

plugins/chat/spec/requests/core_ext/users_controller_spec.rb

@@ -31,7 +31,7 @@ describe UsersController do
 
     before do
       register_test_bookmarkable(Chat::MessageBookmarkable)
-      SiteSetting.chat_allowed_groups = [chatters]
+      SiteSetting.chat_allowed_groups = chatters
       sign_in(current_user)
     end