Fix db seeds for Solid Queue

db/seeds.rb still required "sidekiq/testing" and wrapped seeding in
Sidekiq::Testing.inline!, but Sidekiq is no longer in the bundle after
the Solid Queue migration, so `rails db:setup` failed with a LoadError.

Run the jobs triggered while seeding inline via Active Job instead,
restoring the previous behavior with the adapter the app actually uses.

db/seeds.rb

@@ -1,8 +1,9 @@
-require 'sidekiq/testing'
-
 ldap = LdapService.new
 
-Sidekiq::Testing.inline! do
+original_queue_adapter = ActiveJob::Base.queue_adapter
+ActiveJob::Base.queue_adapter = :inline
+
+begin
   ldap.delete_all_users!
 
   puts "Create user: admin"
@@ -25,4 +26,6 @@ Sidekiq::Testing.inline! do
       password: "user is user", confirmed: true
     })
   end
+ensure
+  ActiveJob::Base.queue_adapter = original_queue_adapter
 end