Silence _perform method redefinition warning

I'd like to get rid of this noisy warning:

```shell
sentry-rails-5.26.0/lib/sentry/rails/background_worker.rb:5: warning: method redefined; discarding old _perform
sentry-ruby-5.26.0/lib/sentry/background_worker.rb:74: warning: previous definition of _perform was here
```

#skip-changelog

# Please enter the commit message for your changes. Lines starting
# with '#' will be kept; you may remove them yourself if you want to.
# An empty message aborts the commit.
#
# Date:      Sun Aug 24 01:04:29 2025 +0400
#
# On branch silence-perform-method-redefinition-warning
# Changes to be committed:
#	modified:   lib/sentry/rails/background_worker.rb
#

Author: viralpraxis

sentry-rails/lib/sentry/rails/background_worker.rb

@@ -2,13 +2,13 @@
 
 module Sentry
   class BackgroundWorker
-    def _perform(&block)
-      block.call
-    ensure
-      # some applications have partial or even no AR connection
-      if ActiveRecord::Base.connected?
-        # make sure the background worker returns AR connection if it accidentally acquire one during serialization
-        ActiveRecord::Base.connection_pool.release_connection
+    prepend Module.new do
+      def _perform(&block)
+        super(&block)
+      ensure
+        if ActiveRecord::Base.connected?
+          ActiveRecord::Base.connection_pool.release_connection
+        end
       end
     end
   end