Aws organizations account idempotency

[ramsriu]

Title: Implement idempotency for account creation in CreateHandler

Description:
This PR implements idempotency for account creation in the CreateHandler of the AWS Organizations Account resource. The changes ensure that attempting to create an account that already exists results in an appropriate error response rather than attempting to create a duplicate account.

Key Changes:

1. Modified CreateHandler to check for existing accounts before attempting creation.
2. Implemented a new checkIfAccountExists method to perform the existence check.
3. Updated handleRequest method to return an AlreadyExists error when an account with the same email is found.
4. Updated CallbackContext to track the pre-existence check and account creation status.
5. Refactored unit tests to align with the new idempotent behavior.

Specific Updates:

• In CreateHandler:

  • Added checkIfAccountExists method to query existing accounts.
  • Updated handleRequest to use checkIfAccountExists and handle already existing accounts.
  • Modified error handling to return appropriate error codes and messages.

• In CreateHandlerTest:

  • Updated existing test cases to account for the new idempotency check.
  • Added new test cases:
    • handleRequest_checkIfAccountExists_AccountAlreadyExists
    • handleRequest_checkIfAccountExists_AccountDoesNotExist
  • Modified other affected test cases to align with the new behavior.

• In CallbackContext:

  • Added isPreExistenceCheckComplete and isDidResourceAlreadyExist flags.

Testing:

• All existing unit tests have been updated and pass.
• New unit tests have been added to cover the idempotency scenarios.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[pns-amzn]

isDidResourceAlreadyExist -> didResourceAlreadyExist

Without this update, will isDidResourceAlreadyExist and setDidResourceAlreadyExist work correctly?

[ramsriu]

yes the Functionality of it doesn't have any affect(if it has any may be I would have caught in the unit tests), it is the name that looks a bit redundant may be not following the naming conventions in java properly, I followed because to maintain similarity with the other intializations