When possible, use '@users' decorator. Rename tests to better match their
main purpose, notably
* test_mail_track*: mail_track specific (specific fields, display)
* test_message_track*: overall behavior of 'message_track', notably subtypes,
template usage, ...
Add some additional tests and improve test coverage, as some field types
were not covered (date, datetime, text notably). Improve currency
check for monetary fields.
Move 'mail.tracking.duration.mixin' tests into the file testing mixins
linked to 'mail.thread', rename the Case class according to current test
guidelines.
Also starting from now, `MailCommon` flushes tracking automatically at
setup time, allowing to remove some custom flush done in tests. That way
tests are less prone to non deterministic errors. This implies some changes
in execution of tests, which means some updated query counters notably.
Task-3345979 (Mail: Simplify tracking model)
Part-of: odoo/odoo#124182
Thibault Delavallée
c40053bc28