2982: Adapt task queries to account for special index swap rules r=irevoire a=loiclec
# Pull Request
## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/2970
## What does this PR do?
- Replace the `get_tasks` method with a `get_tasks_from_authorized_indexes` which returns the list of tasks matched by the query **from the point of view of the user**. That is, it takes into consideration the list of authorised indexes as well as the special case of `IndexSwap` which should not be returned if an index_uid is specified or if any of its associated indexes are not authorised.
- Adapt the code in other places following this change
- Add some tests
- Also the method `get_task_ids_from_authorized_indexes` now takes a read transaction as argument. This is because we want to make sure that the implementation of `get_tasks_from_authorized_indexes` only uses one read transaction. Otherwise, we could (1) get a list of task ids matching the query, then (2) one of these task ids is deleted by a taskDeletion task, and finally (3) we try to get the `Task`s associated with each returned task ids, and get a `CorruptedTaskQueue` error.
Co-authored-by: Loïc Lecrenier <loic.lecrenier@me.com>
And make index_not_found error asynchronous, since we can't know
whether the index will exist by the time the index swap task is
processed.
Improve the index-swap test to verify that future tasks are not swapped
and to test the new error messages that were introduced.
