### Elasticsearch Version

8.11.0

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

MacOS

### Problem Description

When sending a ESQL query with the `enrich` command that involves a policy that does not existing a `NullPointerException` is thrown and shown as error messages to the user:

Query:
```
row a  = 1| enrich missing-policy
```

Returns:
```
null_pointer_exception - Cannot invoke "org.elasticsearch.xpack.core.enrich.EnrichPolicy.getMatchField()" because "policy" is null
```

### Steps to Reproduce

See above.

### Logs (if relevant)

_No response_
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/AnalyzerTests.java
public void testDateFormatOnText() {
        verifyUnsupported("""
            from test
            | eval date_format(keyword)
            """, "first argument of [date_format(keyword)] must be [datetime], found value [keyword] type [keyword]");
    }
    public void testDateFormatWithNumericFormat() {
        verifyUnsupported("""
            from test
            | eval date_format(1, date)
            """, "first argument of [date_format(1, date)] must be [string], found value [1] type [integer]");
    }
    public void testDateFormatWithDateFormat() {
        verifyUnsupported("""
            from test
            | eval date_format(date, date)
            """, "first argument of [date_format(date, date)] must be [string], found value [date] type [datetime]");
    }
    public void testDateParseOnInt() {
        verifyUnsupported("""
            from test
            | eval date_parse(keyword, int)
            """, "second argument of [date_parse(keyword, int)] must be [string], found value [int] type [integer]");
    }
    public void testDateParseOnDate() {
        verifyUnsupported("""
            from test
            | eval date_parse(keyword, date)
            """, "second argument of [date_parse(keyword, date)] must be [string], found value [date] type [datetime]");
    }