PERF: Load all common passwords in one go (#15986)

Revert "BUGFIX: use a more widely compatible version of sadd"

This reverts commit aa577f11fd.

I think the compatibility might not be a problem anymore, after 8 years? 😃

lib/common_passwords/common_passwords.rb

@@ -44,10 +44,7 @@ class CommonPasswords
 
   def self.load_passwords
     passwords = File.readlines(PASSWORD_FILE)
-    passwords.map!(&:chomp).each do |pwd|
-      # slower, but a tad more compatible
-      redis.sadd LIST_KEY, pwd
-    end
+    redis.sadd LIST_KEY, passwords.map!(&:chomp)
   rescue Errno::ENOENT
     # tolerate this so we don't block signups
     Rails.logger.error "Common passwords file #{PASSWORD_FILE} is not found! Common password checking is skipped."