This patch changes the behaviour of `timeline_limit` in sliding sync
requests. It previously was sticky, but since it's now mandatory
with MSC4186, it's preferable it to be non-sticky, otherwise in
some scenarios it might default to 0 (its default value). How?
If the server doesn't reply with our `txn_id` (because it doesn't
support sticky parameters or because it misses a `txn_id`), the
next request will be built with a default `timeline_limit` value,
which is zero, and won't get updated to the `timeline_limit` value
from `SlidingSyncListStickyParameters`. This is not good. Instead,
we must consider `timeline_limit` as non-sticky, and moves it from
`SlidingSyncListStickyParameters` to `SlidingSyncListInner`. This is
what this patch does.
Ivan Enderlin
4d45b02e91