### 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_
server/src/test/java/org/elasticsearch/cluster/metadata/MetadataIndexTemplateServiceTests.java
.startObject("properties")
                    .startObject("field2")
                    .field("type", "text")
                    .field("analyzer", "custom_1")
                    .endObject()
                    .endObject()
                    .endObject()
            )
        );
        List<Throwable> errors = putTemplateDetail(request);
        assertThat(errors.size(), equalTo(1));
        assertThat(errors.get(0), instanceOf(MapperParsingException.class));
        assertThat(errors.get(0).getMessage(), containsString("analyzer [custom_1] has not been configured in mappings"));
    }
    public void testAliasInvalidFilterInvalidJson() throws Exception {
        
        PutRequest request = new PutRequest("api", "blank_mapping");
        request.patterns(singletonList("te*"));
        request.mappings(new CompressedXContent("{}"));
        Set<Alias> aliases = new HashSet<>();
        aliases.add(new Alias("invalid_alias").filter("abcde"));
        request.aliases(aliases);
        List<Throwable> errors = putTemplateDetail(request);
        assertThat(errors.size(), equalTo(1));
        assertThat(errors.get(0), instanceOf(IllegalArgumentException.class));
        assertThat(errors.get(0).getMessage(), equalTo("failed to parse filter for alias [invalid_alias]"));
    }
    public void testIndexTemplateWithAlias() throws Exception {
        final String templateName = "template_with_alias";
        final String aliasName = "alias_with_settings";