Add support for MSC4155 Invite filtering (#18288)

This implements
https://github.com/matrix-org/matrix-spec-proposals/pull/4155, which
adds support for a new account data type that blocks an invite based on
some conditions in the event contents.

---------

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

docker/complement/conf/workers-shared-extra.yaml.j2

@@ -127,6 +127,8 @@ experimental_features:
   msc3983_appservice_otk_claims: true
   # Proxy key queries to exclusive ASes
   msc3984_appservice_key_query: true
+  # Invite filtering
+  msc4155_enabled: true
 
 server_notices:
   system_mxid_localpart: _server