This PR fixes two translation issues when launching a chat bot with a
different language than the user's:
1. Wrong translation for `question_selection` answers
2. Wrong translation for the `question_email` answers
1. The answers to a `question_selection` could be mistranslated
because the lang is missing from the context when `post_welcome_steps`
is called`. As a result, the `discuss.channel/new_message`
notification would have the wrong answers format.
Steps to reproduce the issue:
- Go to the test chat bot test page
- Switch the website language to the one that is not used by the user.
- Check the return result of `post_welcome_steps`: answers are in the
correct language.
- Check the corresponding `discuss.channel/new_message` notification
received through the websocket: the language is the one of the user.
2. The chat bot language is not specified when calling the
`validate_email` route so the lang is the one of the user by default.
Steps to reproduce the issue:
- Go to the chat bot test page
- Activate another language than the one of the user
- Select "I have a pricing question" with no operator available
- Enter an invalid email
- The answer is in the user's language while it should not
opw-3862125
closesodoo/odoo#162655
Signed-off-by: Matthieu Stockbauer (tsm) <tsm@odoo.com>