Support email translations

Here is a case where email templates translation is important: I am using ECA and Easy Email to send HTML email to an user who has just created their account on a bilingual site and I need the email to be in the interface language during registration.
If I activate content translation for emails, I can see the list of template fields (To, BC, Body...) but if I go to the translation tab of my template, I can only translate the title of the template (which is visible only for admin).
Is there a configuration that I'm missing or will I be forced to create two templates (one for each language) and create two paths of actions on my ECA model, with a condition based on the interface language during registration?

I've included some of the work that was done here in this issue in the 3.0.x branch.

Note that it requires a special upgrade process due to the changing of the entity type. I've described the process in the release notes here: https://www.drupal.org/project/easy_email/releases/3.0.0-beta3 →

I did some limited testing with adding a second language to my site and translating an email template. It appeared to work. But, I'm not an expert in multilingual sites, so it would be great if others could report back about the multilingual functionality of the 3.0.x branch when test it out.

Setting the status back to active here because the patch no longer needs to be reviewed. If there are additional updates needed to the 3.0.x branch, post them and change the status back to needs review.

Thank you for this big update.
I tested on a fresh website with ECA and the change made for the translation fulfills exactly the role I expected. I was able to create a template then translate it in full (subject, title, etc.) and when I add a Send Easy Email action on ECA, if the event triggers from the English version, the email sent is the one translated into English. If the event triggers from the French version, it is the email in French which arrives in the targeted mailbox. No more need to create 2 different email templates and add a test on the language of the site to send translated emails from ECA. The model is considerably simplified and pragmatic. Thanks again!

Okay, I'm going to mark this issue as fixed, since I believe it's now possible to send translated emails from the 3.0.x branch.

I've added a follow-up issue to improve the UI for translation: ✨ Improve Translation User Interface Active

I don't have an immediate need for that improvement, since I don't have a multilingual site I'm supporting. That means I'm not going to get to it anytime soon. If someone else who is using translations wants to take that on, it would be much appreciated.

Thanks to everyone who helped on this issue!

Automatically closed - issue fixed for 2 weeks with no activity.