We are currently lacking an index with (author, failure) due to the information
being spread out in two different tables which are both rather big (there are a
lot of non-failure messages for the current user, as well as a lot of failure
messages for other users), so the fetch of failures for the current user can
become extremely slow (> 20s).
With this new index, the query takes less than 1ms.
task-2742946
closesodoo/odoo#83451
Related: odoo/upgrade#3204
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>