Bitbucket Cloud - Draft Pull Request Support

[nazzer23]

Bitbucket Cloud Pull Request - add the ability to be able to detect if a Pull Request is a Draft - assume false for when Payload doesn't provide draft key.

Testing done

Ran the included maven tests and within testProcessPullRequestApprovalWebhookGit - I outputted actionCaptor.getValue().getPayload().getPullRequest() to ensure that draft=false - as draft isn't included in the existing dataset.
Bitbucket Cloud Event Payloads (https://support.atlassian.com/bitbucket-cloud/docs/event-payloads/#Pull-request) specify that the Pull Request object should return draft. This may not be happening in practice as it appears to have only been incorporated into Bitbucket Cloud in the last 6 months.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed