feat: remove strip_received_headers config option

This previously removed all Received headers which were sent to the smtp
server when enabled. This is not something that should be happening.

config/postal.defaults.yml

@@ -72,7 +72,6 @@ smtp_server:
   ssl_version: <%= ENV.fetch('SMTP_SERVER_SSL_VERSION', 'SSLv23') %>
   proxy_protocol: <%= ENV.fetch('SMTP_SERVER_PROXY_PROTOCOL', 'false') %>
   log_connect: <%= ENV.fetch('SMTP_SERVER_LOG_CONNECT', 'false') %>
-  strip_received_headers: <%= ENV.fetch('SMTP_SERVER_STRIP_RECEIVED_HEADERS', 'false') %>
   max_message_size: <%= ENV.fetch('SMTP_SERVER_MAX_MESSAGE_SIZE', '14') %> # size in Megabytes
 
 smtp_relays:

lib/postal/smtp_server/client.rb

@@ -393,15 +393,10 @@ module Postal
                 if @header_key && @headers[@header_key.downcase] && @headers[@header_key.downcase].last
                   @headers[@header_key.downcase].last << data.to_s
                 end
-                # If received headers are configured to be stripped and we're currently receiving one
-                # skip the append methods at the bottom of this loop.
-                next if Postal.config.smtp_server.strip_received_headers? && @header_key && @header_key.downcase == "received"
               else
                 @header_key, value = data.split(/:\s*/, 2)
                 @headers[@header_key.downcase] ||= []
                 @headers[@header_key.downcase] << value
-                # As above
-                next if Postal.config.smtp_server.strip_received_headers? && @header_key && @header_key.downcase == "received"
               end
             end
             @data << data