[Bug]: Email is not sent to the author when blocking with a reason

[ioanarusiczki]

What happened?

Create a block such as https://reviewers.addons-dev.allizom.org/en-US/reviewers/review/630490
without adding a canned reason (or a custom one)

Check for an email sent to the author.

What did you expect to happen?

An email + the reason the add-on is blocked.

Is there an existing issue for this?

• I have searched the existing issues

┆Issue is synchronized with this Jira Task

[eviljeff]

Blocklisting integration is known area where the emails are incorrect right now. The reasons are missing as you note (there isn't anywhere in the blocklist tool UI to select them) and the rest of the text incorrectly states the version will still be usable by existing users - which is not correct for versions in the blocklist.

The work is summarized in https://mozilla-hub.atlassian.net/browse/AMO-228