Fixed issues identified in Idempotency QA testing

[Ashi1993]

Fixed issues identified in Idempotency QA testing

This PR contains the fixes for issues identified in Idempotency QA testing

Issue link: #186, https://github.com/wso2-enterprise/ob-compliance-toolkit-berlin/issues/188

Doc Issue: wso2/docs-open-banking#881

Applicable Labels: OB 3.0.0, Berlin Toolkit

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Development Checklist

1. Build complete solution with pull request in place.
2. Ran checkstyle plugin with pull request in place.
3. Ran Findbugs plugin with pull request in place.
4. Ran FindSecurityBugs plugin and verified report.
5. Formatted code according to WSO2 code style.
6. [ x Have you verified the PR doesn't commit any keys, passwords, tokens, usernames, or other secrets?
7. Migration scripts written (if applicable).
8. Have you followed secure coding standards in WSO2 Secure Engineering Guidelines?

Testing Checklist

1. Written unit tests.
2. Verified tests in multiple database environments (if applicable).
3. Tested with BI enabled (if applicable).