### Elasticsearch Version

8.1.1

### Installed Plugins

_No response_

### Java Version

_bundled_

###  OS Version

Darwin Kernel Version 21.4.0

### Problem Description

Under certain conditions, executing a range enrich policy on a field with wrong datatype gives a NPE instead of a more comprehensible error.

### Steps to Reproduce

```
PUT enrich_index
{
  "mappings": {
    "properties": {
      "object": {
        "properties": {
          "field": {
            "type": "keyword"
          }
        }
      }
    }
  }
}

PUT /_enrich/policy/enrich_policy
{
  "range": {
    "indices": "enrich_index",
    "match_field": "object",
    "enrich_fields": ["enrich_field"]
  }
}

POST /_enrich/policy/enrich_policy/_execute
```

Executing the policy returns:
```json
{
  "error" : {
    "root_cause" : [
      {
        "type" : "null_pointer_exception",
        "reason" : "Cannot invoke \"String.hashCode()\" because \"<local7>\" is null"
      }
    ],
    "type" : "null_pointer_exception",
    "reason" : "Cannot invoke \"String.hashCode()\" because \"<local7>\" is null"
  },
  "status" : 500
}
```

Interestingly enough, if the enrich index were created like this (without subfield in `object`):
```
PUT enrich_index
{
  "mappings": {
    "properties": {
      "object": {
        "properties": {
        }
      }
    }
  }
}
```
 

Executing the policy would return a much better error:
```json
{
  "error" : {
    "root_cause" : [
      {
        "type" : "exception",
        "reason" : "Field 'object' has type [object] which doesn't appear to be a range type"
      }
    ],
    "type" : "exception",
    "reason" : "Field 'object' has type [object] which doesn't appear to be a range type"
  },
  "status" : 500
}
```



### Logs (if relevant)

_No response_
x-pack/plugin/enrich/src/main/java/org/elasticsearch/xpack/enrich/EnrichPolicyRunner.java
case "double_range":
                case "ip_range":
                    return createEnrichMappingBuilder((builder) -> builder.field("type", type).field("doc_values", false));
                
                case "date_range":
                    Set<String> formatEntries = matchFieldMappings.stream().map(map -> map.get("format")).collect(Collectors.toSet());
                    if (formatEntries.size() == 1) {
                        return createEnrichMappingBuilder((builder) -> {
                            builder.field("type", type).field("doc_values", false);
                            String format = formatEntries.iterator().next();
                            if (format != null) {
                                builder.field("format", format);
                            }
                            return builder;
                        });
                    }
                    if (formatEntries.isEmpty()) {
                        
                        return createEnrichMappingBuilder((builder) -> builder.field("type", type).field("doc_values", false));
                    }
                    throw new ElasticsearchException(
                        "Multiple distinct date format specified for match field '{}' - indices({})  format entries({})",
                        enrichPolicy.getMatchField(),
                        Strings.collectionToCommaDelimitedString(enrichPolicy.getIndices()),
                        (formatEntries.contains(null) ? "(DEFAULT), " : "") + Strings.collectionToCommaDelimitedString(formatEntries)
                    );
                default:
                    throw new ElasticsearchException(
                        "Field '{}' has type [{}] which doesn't appear to be a range type",
                        enrichPolicy.getMatchField(),