* Fix regression for select tag helper with array

v6.1.0.rc1 does not generate DOM with the selected attribute
when the object's method returns an array.
This is because it has been changed by #34809 to always convert
to a string.

This commit fixes the issue.

## Steps to reproduce

```ruby
# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", ENV["RAILS_VERSION"]
end

require "action_view"
require "minitest/autorun"

class BugTest < ActionView::TestCase
  Post = Struct.new("Post", :tags)

  def test_stuff
    @post = Post.new
    @post.tags = ["foo", "bar"]
    expected = <<~DOM.strip
      <select name="post[tags]" id="post_tags"><option selected="selected" value="foo">foo</option>
      <option selected="selected" value="bar">bar</option>
      <option value="buz">buz</option></select>
    DOM

    assert_dom_equal(expected, select("post", "tags", %W(foo bar buz), { multiple: true }))
  end
end
```

The test succeeds on v6.0.3.4, but the test fails on v6.1.0.rc1.

* Update actionview/lib/action_view/helpers/tags/select.rb

[Takumi Shotoku + Rafael Mendonça França]