DEV: Remove unnecessary thread in `Jobs::Base::JobInstrumenter` (#30179)

In `Jobs::Base::JobInstrumenter.raw_log`, we were creating an instance
of `Queue` and then pushing messages to the queue before popping it off
the queue in a thread. However, this complexity is not necessary when
we can just write directly to the logger without much overhead. This is
how all logging is done in other parts of the app as well.

app/jobs/base.rb

@@ -44,6 +44,7 @@ module Jobs
     class JobInstrumenter
       def initialize(job_class:, opts:, db:, jid:)
         return unless enabled?
+
         self.class.mutex.synchronize do
           @data = {}
 
@@ -75,6 +76,7 @@ module Jobs
 
       def stop(exception:)
         return unless enabled?
+
         self.class.mutex.synchronize do
           profile = MethodProfiler.stop
 
@@ -102,30 +104,15 @@ module Jobs
       end
 
       def self.raw_log(message)
-        @@logger ||=
-          begin
-            f = File.open "#{Rails.root}/log/sidekiq.log", "a"
-            f.sync = true
-            Logger.new f
-          end
-
-        @@log_queue ||= Queue.new
-
-        if !defined?(@@log_thread) || !@@log_thread.alive?
-          @@log_thread =
-            Thread.new do
-              loop do
-                @@logger << @@log_queue.pop
-              rescue Exception => e
-                Discourse.warn_exception(
-                  e,
-                  message: "Exception encountered while logging Sidekiq job",
-                )
-              end
-            end
+        begin
+          logger << message
+        rescue => e
+          Discourse.warn_exception(e, message: "Exception encountered while logging Sidekiq job")
         end
+      end
 
-        @@log_queue.push(message)
+      def self.logger
+        @@logger ||= Logger.new("#{Rails.root}/log/sidekiq.log")
       end
 
       def current_duration
@@ -259,6 +246,7 @@ module Jobs
           requeued = true
           return
         end
+
         parent_thread = Thread.current
         cluster_concurrency_redis_key = self.class.cluster_concurrency_redis_key
 
@@ -343,6 +331,7 @@ module Jobs
         keepalive_thread.join
         self.class.clear_cluster_concurrency_lock!
       end
+
       ActiveRecord::Base.connection_handler.clear_active_connections!
     end
   end