Fix ERB syntax

This change suppresses the following warning:
```
/home/runner/work/resque-scheduler/resque-scheduler/lib/resque/scheduler/server.rb:85: warning: possibly useless use of -@ in void context
```

Author: mishina2228

lib/resque/scheduler/server/views/delayed.erb

@@ -1,5 +1,5 @@
 <h1>Delayed Jobs</h1>
-<%- size = resque.delayed_queue_schedule_size %>
+<% size = resque.delayed_queue_schedule_size %>
 
 <%= scheduler_view :search_form, layout: false %>