fix(web-server): allow for trusted proxies not be set

config/initializers/trusted_proxies.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 Rack::Request.ip_filter = lambda { |ip|
-  if Postal::Config.postal.trusted_proxies.any? { |net| net.include?(ip) } ||
+  if Postal::Config.postal.trusted_proxies&.any? { |net| net.include?(ip) } ||
      ip.match(/\A127\.0\.0\.1\Z|\A::1\Z|\Afd[0-9a-f]{2}:.+|\Alocalhost\Z|\Aunix\Z|\Aunix:/i)
     true
   else