Add resources.consent conditional dependency back (#8107)

Turns out that part of the codebase (synapse.config.server) checks for this key explicitly. Remove that check.

changelog.d/8107.feature

@@ -0,0 +1 @@
+Use the default template file when its equivalent is not found in a custom template directory.

synapse/config/server.py

@@ -26,7 +26,6 @@ import yaml
 
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.http.endpoint import parse_and_validate_server_name
-from synapse.python_dependencies import DependencyException, check_requirements
 
 from ._base import Config, ConfigError
 
@@ -508,8 +507,6 @@ class ServerConfig(Config):
                 )
             )
 
-        _check_resource_config(self.listeners)
-
         self.cleanup_extremities_with_dummy_events = config.get(
             "cleanup_extremities_with_dummy_events", True
         )
@@ -1133,20 +1130,3 @@ def _warn_if_webclient_configured(listeners: Iterable[ListenerConfig]) -> None:
                 if name == "webclient":
                     logger.warning(NO_MORE_WEB_CLIENT_WARNING)
                     return
-
-
-def _check_resource_config(listeners: Iterable[ListenerConfig]) -> None:
-    resource_names = {
-        res_name
-        for listener in listeners
-        if listener.http_options
-        for res in listener.http_options.resources
-        for res_name in res.names
-    }
-
-    for resource in resource_names:
-        if resource == "consent":
-            try:
-                check_requirements("resources.consent")
-            except DependencyException as e:
-                raise ConfigError(e.message)