### Elasticsearch Version

8.5.0

### Installed Plugins

_No response_

### Java Version

elastic.co customer

### OS Version

elastic.co customer

### Problem Description

Dynamic mapping eagerly interprets a string with this format `2021-51` as a date field, but then fails to index due to 51 not being a valid month.

Expected behaviour would be to index `2021-51` as a text field.

### Steps to Reproduce

With [dynamic mapping](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic-mapping.html) turned on attempt to index this document in a fresh, empty index:

```http
POST /bugreport/_doc
{
  "not_a_date": "2022-51"
}
```

Returned error message is:
```json
{
  "error": {
    "root_cause": [
      {
        "type": "date_time_exception",
        "reason": "date_time_exception: Invalid value for MonthOfYear (valid values 1 - 12): 51"
      }
    ],
    "type": "mapper_parsing_exception",
    "reason": "failed to parse field [not_a_date] of type [date] in document with id 'U1f9Y4YBXO70bNmhk658'. Preview of field's value: '2022-51'",
    "caused_by": {
      "type": "date_time_exception",
      "reason": "date_time_exception: Invalid value for MonthOfYear (valid values 1 - 12): 51"
    }
  },
  "status": 400
}
```

### Logs (if relevant)

Mappings on index `bugreport`

```http
GET /bugreport/_mapping
```

```json
{
  "bugreport": {
    "mappings": {}
  }
}
```
server/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
if (lastDotNdx == -1) {
                
                break;
            }
            String parentName = parentMapper.name().substring(0, lastDotNdx);
            parentMapper = context.mappingLookup().objectMappers().get(parentName);
            if (parentMapper == null) {
                
                parentMapper = context.getDynamicObjectMapper(parentName);
                if (parentMapper == null) {
                    
                    break;
                }
            }
            dynamic = parentMapper.dynamic();
        }
        if (dynamic == null) {
            return context.root().dynamic() == null ? ObjectMapper.Dynamic.TRUE : context.root().dynamic();
        }
        return dynamic;
    }
    
    
    
    
    private static Mapper getMapper(final DocumentParserContext context, ObjectMapper objectMapper, String fieldName) {
        if (context.path().atRoot()) {
            
            Mapper mapper = context.getMetadataMapper(fieldName);
            if (mapper != null) {