In `aws_sdk_eventbridge`, there is no pagination helper for `ListTargetsByRule`

### Describe the feature

Many of the SDK's fluent builders [have a method allow the SDK to handle pagination for you](https://docs.aws.amazon.com/sdk-for-rust/latest/dg/paginating.html). `aws_sdk_eventbridge::operation::list_targets_by_rule::builders::ListTargetsByRuleFluentBuilder` does not. This means you have to manually paginate to retrieve all the rules from the EventBridge `ListTargetsByRule` API.

### Use Case

Retrieving all the targets when calling the EventBridge `ListTargetsByRule` API.

### Proposed Solution

Add [the documented pagination helper](https://docs.aws.amazon.com/sdk-for-rust/latest/dg/paginating.html), please.

### Other Information

Similar to #1205.

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### A note for the community

### Community Note
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Start with aws_sdk_eventbridge::operation::list_targets_by_rule::builders::ListTargetsByRuleFluentBuilder and review the documented Rust SDK pagination helper. Compare the similar request in issue #1205, then verify that ListTargetsByRule supports the helper and that callers can retrieve all targets without manual pagination.

Written by the indexing model from the issue text.