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## Environment
**Liquibase Version**: 3.10

**Database Vendor & Version**: any

**Operating System Type & Version**: any

## Description
Create a custom change with a params list where there is no "name", it will trigger a NullPointerException instead of a nicer validation error explaining the problem.

## Steps To Reproduce
A changelog file with the following customChange:

```
     - customChange:
         class: com.company.customchanges.AddAttribute
         param:
           fieldType: '12'
           mandatory: '1'
           labelKey: userAttribute.firstName
           maxLength: '50'
           index: '2'
           newline: '1'
           readOnly: '1'
           visible: '1'
```

which **was generated by the Liquibase YamlChangelogSerializer!!** (which is a separate issue)
trriggered a NullPointerException.

## Actual Behavior
A NullPointerException without a message.

## Expected/Desired Behavior
A clearer validation error should be thrown indicating the cause of the problem.


}
    @Override
    public Object getSerializableFieldValue(String field) {
        switch (field) {
            case "class":
                return getClassName();
            case "param":
                return this.paramValues;
            default:
                throw new UnexpectedLiquibaseException("Unexpected CustomChangeWrapper field " + field);
        }
    }
    @Override
    public Set<String> getSerializableFields() {
        return new HashSet<>(Arrays.asList("class", "param"));
    }
    @Override
    public String getSerializedObjectNamespace() {
        return STANDARD_CHANGELOG_NAMESPACE;
    }
    @Override
    public void load(ParsedNode parsedNode, ResourceAccessor resourceAccessor) throws ParsedNodeException {
        try {
            setClass(parsedNode.getChildValue(null, "class", String.class));
        } catch (CustomChangeException e) {
            throw new ParsedNodeException(e);
        }
        super.load(parsedNode, resourceAccessor);
    }
    @Override