Use Enumerable#max instead of custom implementation

See
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58578#note_558440931.

app/workers/database/batched_background_migration_worker.rb

@@ -38,7 +38,7 @@ module Database
     end
 
     def with_exclusive_lease(interval)
-      timeout = max(interval * LEASE_TIMEOUT_MULTIPLIER, MINIMUM_LEASE_TIMEOUT)
+      timeout = [interval * LEASE_TIMEOUT_MULTIPLIER, MINIMUM_LEASE_TIMEOUT].max
       lease = Gitlab::ExclusiveLease.new(lease_key, timeout: timeout)
 
       yield if lease.try_obtain
@@ -46,10 +46,6 @@ module Database
       lease&.cancel
     end
 
-    def max(left, right)
-      left >= right ? left : right
-    end
-
     def lease_key
       self.class.name.demodulize.underscore
     end