Enable URL previews in complement homeserver config. (#14198)

changelog.d/14198.misc

@@ -0,0 +1 @@
+Enable url previews when testing with complement.

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

@@ -12,6 +12,8 @@ trusted_key_servers: []
 enable_registration: true
 enable_registration_without_verification: true
 bcrypt_rounds: 4
+url_preview_enabled: true
+url_preview_ip_range_blacklist: []
 
 ## Registration ##