Add missing autoload `Type` (#31123)

Attribute modules (`Attribute`, `Attributes`, `AttributeSet`) uses
`Type`, but referencing `Type` before the modules still fail.

```
% ./bin/test -w test/cases/attribute_test.rb -n test_with_value_from_user_validates_the_value
Run options: -n test_with_value_from_user_validates_the_value --seed 31876

E

Error:
ActiveModel::AttributeTest#test_with_value_from_user_validates_the_value:
NameError: uninitialized constant ActiveModel::AttributeTest::Type
    /Users/kamipo/src/github.com/rails/rails/activemodel/test/cases/attribute_test.rb:233:in `block in <class:AttributeTest>'

bin/test test/cases/attribute_test.rb:232

Finished in 0.002985s, 335.0479 runs/s, 335.0479 assertions/s.
1 runs, 1 assertions, 0 failures, 1 errors, 0 skips
```

Probably we need more autoloading at least `Type`.

2 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 0e036f05f5..5de6503144 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -104,6 +104,7 @@ module ActiveRecord
 
     autoload :Result
     autoload :TableMetadata
+    autoload :Type
   end
 
   module Coders
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index e3aab8dad8..345983a655 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "active_record/type"
 require "active_record/connection_adapters/determine_if_preparable_visitor"
 require "active_record/connection_adapters/schema_cache"
 require "active_record/connection_adapters/sql_type_metadata"