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
/**
     * Gets the total number of open shards from all indices. Includes
     * replicas, but does not include shards that are part of closed indices.
     * @return The total number of open shards from all indices.
     */
    public int getTotalOpenIndexShards() {
        return this.totalOpenIndexShards;
    }
    @Override
    public Iterator<IndexMetadata> iterator() {
        return indices.values().iterator();
    }
    public Stream<IndexMetadata> stream() {
        return indices.values().stream();
    }
    public int size() {
        return indices.size();
    }
    public static boolean isGlobalStateEquals(Metadata metadata1, Metadata metadata2) {
        if (metadata1.coordinationMetadata.equals(metadata2.coordinationMetadata) == false) {
            return false;
        }
        if (metadata1.persistentSettings.equals(metadata2.persistentSettings) == false) {
            return false;
        }
        if (metadata1.hashesOfConsistentSettings.equals(metadata2.hashesOfConsistentSettings) == false) {
            return false;
        }
        if (metadata1.templates.equals(metadata2.templates()) == false) {
            return false;