API: Add STRAIGHT_JOIN to ApiQueryUserContribs to avoid planner oddness

API: Add STRAIGHT_JOIN to ApiQueryUserContribs to avoid planner oddness

For some unknown reason, when the `actor` table has few enough rows (or
few enough compared to `revision_actor_temp`) MariaDB 10.1.37 decides it
makes more sense to fetch everything from `actor` + `revision_actor_temp`
and filesort rather than fetching the limited number of rows from
`revision_actor_temp`.

We can work around it by telling it to not reorder the query, but then
(unlike in I9da981c0) we also have to reorder it ourselves to put
`revision_actor_temp` first instead of `revision`.

Bug: T221511
Change-Id: Ic63875b26a051a2da58374d5d76c95a6fa8ecc8e