Seen in an exception stack trace: we are wrapping `ApiFilteringActionFilter` around itself many times, once per filtered action, so effectively every action is doing a linear scan of the filtered actions, implemented recursively. I'm pretty sure a hashmap would be more efficient, and would avoid inflating the stack so much too.

```
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:86) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.action.support.ActionFilter$Simple.apply(ActionFilter.java:53) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at co.elastic.elasticsearch.api.validation.PublicSettingsValidationActionFilter.apply(PublicSettingsValidationActionFilter.java:101) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.core.api.filtering.ApiFilteringActionFilter.apply(ApiFilteringActionFilter.java:53) ~[?:?]
    at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:84) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
    at org.elasticsearch.xpack.security.action.filter.SecurityActionFilter.lambda$applyInternal$3(SecurityActionFilter.java:163) ~[?:?]
    at org.elasticsearch.action.ActionListenerImplementations$DelegatingFailureActionListener.onResponse(ActionListenerImplementations.java:212) ~[elasticsearch-8.11.0-SNAPSHOT.jar:?]
```
server/src/main/java/org/elasticsearch/action/ActionModule.java
private static final Logger logger = LogManager.getLogger(ActionModule.class);
    /**
     *  This RestHandler is used as a placeholder for any routes that are unreachable (i.e. have no ServerlessScope annotation) when
     *  running in serverless mode. It does nothing, and its handleRequest method is never called. It just provides a way to register the
     *  routes so that we know they do exist.
     */
    private static final RestHandler placeholderRestHandler = (request, channel, client) -> {};
    private final Settings settings;
    private final IndexNameExpressionResolver indexNameExpressionResolver;
    private final IndexScopedSettings indexScopedSettings;
    private final ClusterSettings clusterSettings;
    private final SettingsFilter settingsFilter;
    private final List<ActionPlugin> actionPlugins;
    private final Map<String, ActionHandler<?, ?>> actions;
    private final ActionFilters actionFilters;
    private final AutoCreateIndex autoCreateIndex;
    private final DestructiveOperations destructiveOperations;
    private final RestController restController;
    
    private final Set<RestHeaderDefinition> headersToCopy;
    private final RequestValidators<PutMappingRequest> mappingRequestValidators;
    private final RequestValidators<IndicesAliasesRequest> indicesAliasesRequestRequestValidators;