Set record_timestamps = true in AR::InternalMetadata

Fix: https://github.com/rails/rails/issues/42983

The usefulness of these timestamps is a bit questionable,
but I suppose they could be useful for debugging, and
removing them would require to ship a migration etc.

Since `record_timestamps` is now a `class_attribute` we
can simply force it to `true` in just that class.

activerecord/CHANGELOG.md

@@ -1,3 +1,10 @@
+*   Fix `ActiveRecord::InternalMetadata` to not be broken by `config.active_record.record_timestamps = false`
+
+    Since the model always create the timestamp columns, it has to set them, otherwise it breaks
+    various DB management tasks.
+
+    Fixes #42983
+
 *   Add `ActiveRecord::QueryLogs`.
 
     Configurable tags can be automatically added to all SQL queries generated by Active Record.

activerecord/lib/active_record/internal_metadata.rb

@@ -10,6 +10,8 @@ module ActiveRecord
   # This is enabled by default. To disable this functionality set
   # `use_metadata_table` to false in your database configuration.
   class InternalMetadata < ActiveRecord::Base # :nodoc:
+    self.record_timestamps = true
+
     class << self
       def enabled?
         ActiveRecord::Base.connection.use_metadata_table?