NIFI-15480: Added ability to drop FlowFiles selectively using a Predi…

[markap14]

…cate

Added system tests to verify selective dropping of flowfiles from a Connector. Also made significant updates so that diagnostic bundles are captured when a system test fails and diagnostic bundle also contains details of each Connection's FlowFileQueue. This was necessary in aiding the debugging of the new feature but is also something that has been missing for some time.

Summary

NIFI-00000

Tracking

Please complete the following tracking steps prior to pull request creation.

Issue Tracking

• Apache NiFi Jira issue created

Pull Request Tracking

• Pull Request title starts with Apache NiFi Jira issue number, such as NIFI-00000
• Pull Request commit message starts with Apache NiFi Jira issue number, as such NIFI-00000
• Pull request contains commits signed with a registered key indicating Verified status

Pull Request Formatting

• Pull Request based on current revision of the main branch
• Pull Request refers to a feature branch with one commit containing changes

Verification

Please indicate the verification steps performed prior to pull request creation.

Build

• Build completed using ./mvnw clean install -P contrib-check
  • JDK 21
  • JDK 25

Licensing

• New dependencies are compatible with the Apache License 2.0 according to the License Policy
• New dependencies are documented in applicable LICENSE and NOTICE files

Documentation

• Documentation formatting appears as expected in rendered files