The stream-session is the receiving end of streaming, it reads the
mutation fragment stream from an RPC stream and writes it onto the disk.
As such, this part does no disk IO and therefore, using a permit with
count resources is superfluous. Furthermore, after
d98708013c, the count resources on this
permit can cause a deadlock on the receiver end, via the
`db::view::check_view_update_path()`, which wants to read the content of
a system table and therefore has to obtain a permit of its own.
Switch to a tracking-only permit, primarily to resolve the deadlock, but
also because admission is not necessary for a read which does no IO.
Refs: scylladb/scylladb#20885 (partial fix, solves only one of the deadlocks)
Fixes: scylladb/scylladb#21264
(cherry picked from commit dbb26da2aa)
Closesscylladb/scylladb#21303
b78675270e