Add a test to ensure Index Metadata is incremented if system flag flipped to true

[cwperks]

Description

This PR is a WIP to add a test to assert that the index metadata is incremented in cases where the system flag is flipped to true.

This scenario can occur if a plugin utilizes a system index, but previously did not register with SystemIndexPlugin.getSystemIndexDescriptors. If the index already exists and a node is upgraded to a version where the plugin registers the system index with SystemIndexPlugin.getSystemIndexDescriptors, then the flag is flipped to true but the metadata version is not incremented accordingly.

Run the test using ./gradlew integrationTest --tests SystemIndexUpgradeTests -i

Check List

• New functionality includes testing
• New functionality has been documented
• New Roles/Permissions have a corresponding security dashboards plugin PR
• API changes companion pull request created
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.