Hide erb:authentication generator from help text

Before:
```
$ bin/rails g

Usage:
  bin/rails generate GENERATOR [args] [options]

General options:
  -h, [--help]     # Print generator's options and usage
  -p, [--pretend]  # Run but do not make any changes
  -f, [--force]    # Overwrite files that already exist
  -s, [--skip]     # Skip files that already exist
  -q, [--quiet]    # Suppress status output

Please choose a generator below.

Rails:
  application_record
  authentication
  benchmark
  channel
  controller
  generator
  helper
  integration_test
  jbuilder
  job
  mailbox
  mailer
  migration
  model
  resource
  scaffold
  scaffold_controller
  script
  system_test
  task

ActiveRecord:
  active_record:application_record
  active_record:multi_db

Erb:
  erb:authentication

SolidCable:
  solid_cable:install
  solid_cable:update

SolidCache:
  solid_cache:install

SolidQueue:
  solid_queue:install

Stimulus:
  stimulus

TestUnit:
  test_unit:authentication
  test_unit:channel
  test_unit:generator
  test_unit:install
  test_unit:mailbox

```

After:
```
$ bin/rails g

Usage:
  bin/rails generate GENERATOR [args] [options]

General options:
  -h, [--help]     # Print generator's options and usage
  -p, [--pretend]  # Run but do not make any changes
  -f, [--force]    # Overwrite files that already exist
  -s, [--skip]     # Skip files that already exist
  -q, [--quiet]    # Suppress status output

Please choose a generator below.

Rails:
  application_record
  authentication
  benchmark
  channel
  controller
  generator
  helper
  integration_test
  jbuilder
  job
  mailbox
  mailer
  migration
  model
  resource
  scaffold
  scaffold_controller
  script
  system_test
  task

ActiveRecord:
  active_record:application_record
  active_record:multi_db

SolidCable:
  solid_cable:install
  solid_cable:update

SolidCache:
  solid_cache:install

SolidQueue:
  solid_queue:install

Stimulus:
  stimulus

TestUnit:
  test_unit:authentication
  test_unit:channel
  test_unit:generator
  test_unit:install
  test_unit:mailbox

```

Diff:
```diff
--- before      2024-12-02 14:55:12.256784107 +0900
+++ after       2024-12-02 14:55:18.893011553 +0900
@@ -36,9 +36,6 @@
   active_record:application_record
   active_record:multi_db

-Erb:
-  erb:authentication
-
 SolidCable:
   solid_cable:install
   solid_cable:update
```

Author: zzak

railties/lib/rails/generators/erb/authentication/authentication_generator.rb

@@ -5,6 +5,8 @@
 module Erb # :nodoc:
   module Generators # :nodoc:
     class AuthenticationGenerator < Rails::Generators::Base # :nodoc:
+      hide!
+
       def create_files
         template "app/views/passwords/new.html.erb"
         template "app/views/passwords/edit.html.erb"