I18n backend fails with whitelisting key functionality.

[lovenic]

Describe the bug

While using i18n backend config.validate_keys = true doesn't work as expected, because we're trying to call

msg = messages.translate("errors.unexpected_key")

        Message.new(
          path: path,
          meta: msg[:meta] || EMPTY_HASH,
          text: msg[:text],
          predicate: nil,
          input: input
        )

but we get TypeError: no implicit conversion of Symbol into Integer from /usr/local/bundle/gems/dry-schema-1.5.6/lib/dry/schema/message_compiler.rb:119:in []'

seems like messages.translate returns array rather than hash with :meta key.

To Reproduce

class BaseContract < Dry::Validation::Contract
  config.messages.backend = :i18n
end

class TestContract < BaseContract
  params do
    config.validate_keys = true

    required(:test).filled(:string)
  end
end

TestContract.new.call({test: 'meow', extra_test: 'bow'})

Expected behavior

It doesn't fails with error and returns failed validation with a correct message.

My environment

• Ruby version: 2.6.3
• OS: MacOS Big Sur