### Elasticsearch Version

8.11.0

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

MacOS

### Problem Description

The following ESQL statement reports and unhandled error:

```
from index | eval round([1.2])
```

Returns the rror:
```
class_cast_exception - class java.util.ImmutableCollections$ListN cannot be cast to class java.lang.Number (java.util.ImmutableCollections$ListN and java.lang.Number are in module java.base of loader 'bootstrap')
```

### Steps to Reproduce

See above

### Logs (if relevant)

_No response_
x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/math/Round.java
if (childrenResolved() == false) {
            return new TypeResolution("Unresolved children");
        }
        TypeResolution resolution = isNumeric(field, sourceText(), FIRST);
        if (resolution.unresolved()) {
            return resolution;
        }
        return decimals == null ? TypeResolution.TYPE_RESOLVED : isInteger(decimals, sourceText(), SECOND);
    }
    @Override
    public boolean foldable() {
        return field.foldable() && (decimals == null || decimals.foldable());
    }
    @Override
    public Object fold() {
        if (field.dataType() == DataTypes.UNSIGNED_LONG) {
            return decimals == null
                ? field.fold()
                : processUnsignedLong(safeToLong((Number) field.fold()), safeToLong((Number) decimals.fold()));
        }
        if (decimals == null) {
            return Maths.round((Number) field.fold(), 0L);
        }
        return Maths.round((Number) field.fold(), ((Number) decimals.fold()).longValue());
    }
    @Evaluator(extraName = "DoubleNoDecimals")
    static double process(double val) {
        return Maths.round(val, 0).doubleValue();
    }
    @Evaluator(extraName = "Int")