feat(cloudfront-origins): add ipAddressType property to Lambda Function URL origins (#35458)

### Issue # (if applicable)

#35450

### Reason for this change

Lambda Function URLs natively support dual-stack IPv4/IPv6 connectivity, but CDK's FunctionUrlOrigin class did not expose the `ipAddressType` property to configure IP protocol preferences. 

### Description of changes

- Added `OriginIpAddressType` enum with `IPV4`, `IPV6`, and `DUALSTACK` options
- Added optional `ipAddressType` property to `FunctionUrlOriginProps` interface using the enum type
- Default behavior follows CloudFormation default (IPv4 only) to avoid breaking changes
- Updated both `FunctionUrlOrigin` and `FunctionUrlOriginWithOAC` classes to pass through the property
- Added test coverage for default behavior, explicit value setting, and OAC integration
- Updated README with usage examples and enum documentation

### Describe any new or updated permissions being added

N/A

### Description of how you validated changes

- Added unit tests covering default behavior when `ipAddressType` is not specified
- Added unit tests for explicit enum value setting (`OriginIpAddressType.IPV4`, `OriginIpAddressType.IPV6`, `OriginIpAddressType.DUALSTACK`)
- Added test with Origin Access Control (OAC)

### Checklist
- [ ] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: matoom-nomu