Refactor filter_events_for_server (#15240)

* Tweak docstring and type hint

* Flip logic and provide better name

* Separate decision from action

* Track a set of strings, not EventBases

* Require explicit boolean options from callers

* Add explicit option for partial state rooms

* Changelog

* Rename param

synapse/federation/sender/per_destination_queue.py

@@ -547,6 +547,8 @@ class PerDestinationQueue:
                         self._server_name,
                         new_pdus,
                         redact=False,
+                        filter_out_erased_senders=True,
+                        filter_out_remote_partial_state_events=True,
                     )
 
                     # If we've filtered out all the extremities, fall back to