A composable index template with no `template` defined in the body is mistakingly always assumed to not be a time series template. Even if it refers to a component template that has the `index.mode` setting set to `time_series` and the component template defines mappings with dimension fields or routing paths.

Incorrectly this causes to create a data stream with a tsdb index *without* time series start and end time settings set. The fact that this can happen is another bug and is being tracked #98833.

What should happen in this case is that a tsdb data stream is created with a valid tsdb backing index (with correctly generated time series start and end time settings).

This bug was found as part investigating #98792 and is the cause of that bug.
server/src/main/java/org/elasticsearch/cluster/metadata/Metadata.java
Property.NodeScope
    );
    public static final ClusterBlock CLUSTER_READ_ONLY_ALLOW_DELETE_BLOCK = new ClusterBlock(
        13,
        "cluster read-only / allow delete (api)",
        false,
        false,
        true,
        RestStatus.FORBIDDEN,
        EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE)
    );
    public static final Metadata EMPTY_METADATA = builder().build();
    public static final String CONTEXT_MODE_PARAM = "context_mode";
    public static final String CONTEXT_MODE_SNAPSHOT = XContentContext.SNAPSHOT.toString();
    public static final String CONTEXT_MODE_GATEWAY = XContentContext.GATEWAY.toString();
    public static final String CONTEXT_MODE_API = XContentContext.API.toString();
    public static final String DEDUPLICATED_MAPPINGS_PARAM = "deduplicated_mappings";
    public static final String GLOBAL_STATE_FILE_PREFIX = "global-";
    private static final NamedDiffableValueSerializer<Custom> CUSTOM_VALUE_SERIALIZER = new NamedDiffableValueSerializer<>(Custom.class);
    private final String clusterUUID;
    private final boolean clusterUUIDCommitted;
    private final long version;
    private final CoordinationMetadata coordinationMetadata;
    private final Settings transientSettings;
    private final Settings persistentSettings;
    private final Settings settings;
    private final DiffableStringMap hashesOfConsistentSettings;
    private final ImmutableOpenMap<String, IndexMetadata> indices;
    private final ImmutableOpenMap<String, Set<Index>> aliasedIndices;
    private final ImmutableOpenMap<String, IndexTemplateMetadata> templates;