PDF receipts issues with different languages

[Zvangi]

User Story

PDF Receipts are important for most cases in most countries. We wanted to use givewp for our non-profit based in France. We are using Translatepress to translate our content to multiple languages. Even though our default content language is English, we use French as our default wordpress language at Wordpress Settings (to generate french receipts). But It uses selected language on Translatepress and ignores the site language. Which causes it to fail at generating pdf receipt.

We would like to force PDF receipts to use French for it's variables such as written amount. There should be an option to force pdf receipts to generate pdf in a given language or always with language specified in wordpress settings. Not the option visitors select on their end for site content.

Because it straight up breaks the plugin. If I choose any other language than default (wordpress settings) language, pdf generation process after donation fails. It downloads a broken pdf. I can download a working pdf from donator dashboard but it's always in english (written amount).

I guess having the plugin and it's add-ons work with multiple other plugins is hard. But the solution I recommend should help a lot of people for their receipts. Would love to be able to simply force the plugin to generate invoices with a given language. Or not use a language detection system at all since it can't generate pdf's for multiple languages properly.

Steps to Reproduce

1. Install givewp along with translatepress
2. Add few languages other than default
3. Try sending a test donation and download the pdf receipt
4. Try downloading the same receipt from donor dashboard

Latest version of plugin, wordpress and PHP.

Acceptance Criteria

We should be able to control the pdf receipt language.