[Feature Request] Allow additional cluster settings to be updated in Test clusters

[amitgalitz]

Is your feature request related to a problem? Please describe

Currently in opensearch plugins we can use ./gradlew run to spin a local cluster which has some of the regular default settings that are seen in OpenSearch like using port 9200 for http and 9300 for transport.
However currently we are unable to easily change these settings when running locally. For example I want to easily test out cross cluster search feature by running two clusters locally that have different http ports, transport ports and cluster names. This would also allow me to easily build github actions that utilize this capability. For example the error I would get now if I try to change this are:

> Testclusters does not allow the following settings to be changed:[cluster.name, http.port, transport.port, node.name] for node{::leaderCluster-0}

Describe the solution you'd like

For other settings we have already added them to the list of settings we can update, for example:
#15906

I wanted to understand why this list of setting is so strict and if there are downside to allowing a lot more updatable settings for testClusters.

Related component

No response

Describe alternatives you've considered

No response

Additional context

No response