When the theme is used with only one language, the consent box doesn't work

[MrGreensWorkshop]

Please check these items before go any further

• [X] I have watched Mr. Green theme tutorials playlist on YouTube.
• [X] I have searched the existing Issues.
• [X] I have searched the existing Discussions.
• [X] I have checked jekyll docs and the answer was not there.
• [X] I have tested in one of these browsers; Safari, Chrome, Firefox. (This project hasn't been tested in other browsers.)

Are you sure this is a bug?

• [X] I'm sure this is definitely a bug.

Describe the bug

When the theme is used with only one language, the consent box doesn't work. Also, this error occurs.

Expected Behavior

The consent box should work whether one language is used or more than one language is used.

Steps To Reproduce

1. Delete the other language folders. (ja, pt)
2. Delete _data/content/projects/ (ja.yml, pt.yml)
3. Delete _data/lang/ (ja.yml, pt.yml)
4. Delete _data/owner/ (ja.yml, pt.yml)
5. Open _data/conf/main.yml
6. Find language_switch_lang_list and set it to language_switch_lang_list: [en]
7. Use bundle exec jekyll serve --watch --safe to run locally
8. Open http://127.0.0.1:4000
9. The consent box will not be shown.

Which browser have you used?

• [X] Chrome
• [X] Safari
• [X] Firefox
• [ ] Other browsers (This project hasn't been tested in other browsers.)

Which device have you used?

• [X] Desktop
• [X] Mobile IOS
• [X] Mobile Android
• [ ] Other platforms (This project hasn't been tested in other devices.)

Anything else?

No response

[MrGreensWorkshop]

The problem, SlidingMsgBox were used for language_translation_offer_box feature and cookie consent box. But SlidingMsgBox was not included when single language is used.

[MrGreensWorkshop]

fixed with PR #135