Revert "DEV: Upgrade Rails to version 7.1 (#27539)"

This reverts commit 2301dddcff8c0efe551c3c3baeeea63dadbe0ea6.

lib/discourse.rb

@@ -954,7 +954,14 @@ module Discourse
   def self.warn(message, env = nil)
     append = env ? (+" ") << env.map { |k, v| "#{k}: #{v}" }.join(" ") : ""
 
-    loggers = Rails.logger.broadcasts
+    if !(Logster::Logger === Rails.logger)
+      Rails.logger.warn("#{message}#{append}")
+      return
+    end
+
+    loggers = [Rails.logger]
+    loggers.concat(Rails.logger.chained) if Rails.logger.chained
+
     logster_env = env
 
     if old_env = Thread.current[Logster::Logger::LOGSTER_ENV]
@@ -1109,7 +1116,16 @@ module Discourse
       end
     end
 
+    schema_cache = ActiveRecord::Base.connection.schema_cache
+
     RailsMultisite::ConnectionManagement.safe_each_connection do
+      # load up schema cache for all multisite assuming all dbs have
+      # an identical schema
+      dup_cache = schema_cache.dup
+      # this line is not really needed, but just in case the
+      # underlying implementation changes lets give it a shot
+      dup_cache.connection = nil
+      ActiveRecord::Base.connection.schema_cache = dup_cache
       I18n.t(:posts)
 
       # this will force Cppjieba to preload if any site has it