NIFI-12852 Refactor TestRecordPath to improve expressiveness and reduce duplication

[EndzeitBegins]

Summary

NIFI-12852

Refactors the test suite for the Record Path DSL to:

• reduce duplication for common test setup
• improving structure by grouping correlating tests under a @Nested class
• improve expressiveness of tests by stating desired behaviour in method names
• adding additional test cases for existing untested behaviour

Tracking

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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

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Build

• Build completed using mvn clean install -P contrib-check
  • JDK 21

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

[EndzeitBegins]

Rebased onto latest commit of main to resolve merge-issue due to NIFI-13643 / #9163 affecting the same file.

[exceptionfactory]

Thanks for the thorough reorganization @EndzeitBegins, the latest version looks good! +1 merging

[EndzeitBegins]

Thank you for the review & merge, @exceptionfactory.