Fix intermittent test failure in getItem_set_eventualConsistent due to eventual consistency

Motivation and Context

The getItem_set_eventualConsistent test was intermittently failing with the following error:

java.lang.AssertionError: 
Expecting actual:
  0.5
to be close to:
  10.0
by less than 1.0 but difference was 9.5.

This failure occurs because the test performs a DynamoDB read immediately after a write operation. Due to DynamoDB's eventually consistent read model, the item may not be immediately available, resulting in a "not found" response that consumes only 0.5 RCUs instead of the expected 10 RCUs for an 80KB item.

Modifications

• Added retry logic to handle eventual consistency delays in DynamoDB
• Implemented a single retry with 200ms delay when the initial read returns null
• Added assertion with descriptive failure message to clearly indicate when item propagation fails
• Added null check before proceeding with capacity assertions to prevent misleading test failures

The fix ensures the test waits for item propagation before validating consumed capacity, eliminating race conditions while maintaining the test's purpose of verifying eventually consistent read capacity consumption.

Testing

• Ran the test multiple times locally to verify it no longer fails intermittently

Screenshots (if appropriate)

License

• I confirm that this pull request can be released under the Apache 2 license