### Elasticsearch Version

7.x, 8.x

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

Darwin 

### Problem Description

A data stream must have an index template that matches it in order to exist.
When managing index templates we want to make sure we don't leave a
data stream without a [corresponding index template](https://github.com/elastic/elasticsearch/blob/acf9968f9d397d755d5ad9fcf815cca23bbeda61/server/src/main/java/org/elasticsearch/cluster/metadata/MetadataIndexTemplateService.java#L918).

The `dataStreamsUsingTemplate` check uses the index pattern of the index 
templates to conclude if a template is used by a data stream, however it should
be enhanced to check the priority too as there can only be only one index template
that matches a data stream and it's the one with the highest priority.

### Steps to Reproduce

Create an ILM policy
```
PUT _ilm/policy/testing_yo
{
  "policy": {
    "phases": {
      "warm": {
	"actions": {
	  "shrink": {
          "number_of_shards": 1
	  }
        }
      }
    } 
  }
}
```

Create an index template with the `data_stream` option:
```
PUT _index_template/logs_data_stream
{
	"index_patterns": [ "logs*", "te*", "bar*" ],
	"data_stream": {},
        "priority": 100,
	"template" : {
	  "settings": {
            "index.number_of_shards": 3,
	    "index.lifecycle.name": "testing"
	  }
	}
}
```

Create the data stream
```
POST logs_test/_doc 
{
  "message": "testing",
  "@timestamp": "1591890611"
}
```

Create a new index template that would match this data stream with a higher priority
```
PUT _index_template/higher_logs_data_stream
{
	"index_patterns": [ "logs*", "te*", "bar*" ],
	"data_stream": {},
        "priority": 500,
	"template" : {
	  "settings": {
            "index.number_of_shards": 3,
	    "index.lifecycle.name": "testing"
	  }
	}
}
```

Attempt to delete the previous, lower priority index template:
```
DELETE _index_template/logs_data_stream
```

### Logs (if relevant)

_No response_
modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamIT.java
CreateIndexRequest createIndexRequest = new CreateIndexRequest("my-index").alias(new Alias("my-alias"));
        assertAcked(client().admin().indices().create(createIndexRequest).actionGet());
        
        DataStreamIT.putComposableIndexTemplate("my-template", List.of("my-*"));
        var request = new CreateDataStreamAction.Request("my-index");
        var e = expectThrows(IllegalStateException.class, () -> client().execute(CreateDataStreamAction.INSTANCE, request).actionGet());
        assertThat(e.getMessage(), containsString("data stream [my-index] conflicts with index"));
    }
    public void testCreateDataStreamWithSameNameAsDataStreamAlias() throws Exception {
        {
            DataStreamIT.putComposableIndexTemplate("my-template", List.of("my-*"));
            var request = new CreateDataStreamAction.Request("my-ds");
            assertAcked(client().execute(CreateDataStreamAction.INSTANCE, request).actionGet());
            var aliasesAddRequest = new IndicesAliasesRequest();
            aliasesAddRequest.addAliasAction(new AliasActions(AliasActions.Type.ADD).index("my-ds").aliases("my-alias"));
            assertAcked(client().admin().indices().aliases(aliasesAddRequest).actionGet());
            var request2 = new CreateDataStreamAction.Request("my-alias");
            var e = expectThrows(
                IllegalStateException.class,
                () -> client().execute(CreateDataStreamAction.INSTANCE, request2).actionGet()
            );
            assertThat(e.getMessage(), containsString("data stream alias and data stream have the same name (my-alias)"));
        }
        {
            assertAcked(client().execute(DeleteDataStreamAction.INSTANCE, new DeleteDataStreamAction.Request("*")).actionGet());
            DataStreamIT.putComposableIndexTemplate(
                "my-template",
                null,
                List.of("my-*"),
                null,