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
}
        }
        /**
         * Iterates the detected duplicates between datastreams and aliases and collects them into the duplicates list as helpful messages.
         */
        private static void collectAliasDuplicates(
            ImmutableOpenMap<String, IndexMetadata> indicesMap,
            DataStreamMetadata dataStreamMetadata,
            Set<String> aliasDuplicatesWithDataStreams,
            ArrayList<String> duplicates
        ) {
            for (String alias : aliasDuplicatesWithDataStreams) {
                // reported var 
                boolean reported = false;
                for (IndexMetadata cursor : indicesMap.values()) {
                    if (cursor.getAliases().containsKey(alias)) {
                        duplicates.add(alias + " (alias of " + cursor.getIndex() + ") conflicts with data stream");
                        reported = true;
                    }
                }
                // This is for a
                if (reported == false && dataStreamMetadata != null && dataStreamMetadata.dataStreams().containsKey(alias)) {
                    duplicates.add("data stream alias and data stream have the same name (" + alias + ")");
                }
            }
        }
        /**
         * Collect all duplicate names across indices and aliases that were detected into a list of helpful duplicate failure messages.
         */
        private static void collectAliasDuplicates(