[docs]: add common retry examples

### URL/Location

https://docs.aws.amazon.com/durable-execution/sdk-reference/error-handling/retries/

### Describe What's Incorrect or Lacking

Add explicit examples for
1. Exponential backoff with max attempts:
2. Fixed interval backoff
3. Conditional retry (retry only specific errors):
4. Disable retries

When the retry strategy returns shouldRetry: false, the step fails immediately without retries. Use this for operations that should not be retried, such as idempotency checks or operations with side effects that cannot be safely repeated.

### Suggested Improvement

_No response_

### Additional Context

_No response_