Improve performance of switching to rooms with lots of servers and ACLs (#8347)
Improve performance of switching to rooms with lots of servers and ACLs (#8347)

* Improve performance of switching to rooms with lots of servers and ACLs

By not processing the *entire* list of servers and ACLs when determining
how to create permalinks, this shaves ~100 ms off of switches into
high-traffic rooms.

* Fix lint

* Ensure that permalink server candidates can't be duplicates
matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk