Issue:
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After registering for an event, you can download the '.ics' file.
This file is not translated into the current user's language.
Solution:
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Use the default user language and, if public,
use the language selected on the website.
A user may wish to have his calendar in his preferred language
by using the English website.
opw-3193663
closesodoo/odoo#135251
X-original-commit: b06c56b9cc3bdca1ac405eb9a7844a43deebd87c
Signed-off-by: Thomas Lefebvre (thle) <thle@odoo.com>