Re-enabling multi-node tests

[joshpalis]

Description

Re-enabled multi-node tests for JDK 21.0.1

Issues Resolved

Coming from PR : #429
Reference run : https://github.com/opensearch-project/flow-framework/actions/runs/7597617988/job/20693132386

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (42e4cd4) 71.87% compared to head (de15bc0) 71.87%.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #431   +/-   ##
=========================================
  Coverage     71.87%   71.87%           
  Complexity      619      619           
=========================================
  Files            78       78           
  Lines          3133     3133           
  Branches        238      238           
=========================================
  Hits           2252     2252           
  Misses          774      774           
  Partials        107      107           

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[joshpalis]

Multi-node failing with :

org.opensearch.flowframework.rest.FlowFrameworkRestApiIT > testCreateAndProvisionRemoteModelWorkflow FAILED
REPRODUCE WITH: ./gradlew ':integTest' --tests "org.opensearch.flowframework.rest.FlowFrameworkRestApiIT.testCreateAndProvisionRemoteModelWorkflow" -Dtests.seed=4E419A2BAF324D00 -Dtests.security.manager=false -Dtests.jvm.argline="-XX:TieredStopAtLevel=1 -XX:ReservedCodeCacheSize=64m" -Dtests.locale=de-AT -Dtests.timezone=Canada/Newfoundland -Druntime.java=21
    org.opensearch.client.ResponseException: method [POST], host [http://[::1]:45229], URI [/_plugins/_flow_framework/workflow/I6eLKY0BjeZ4HVwn6xdD/_provision], status line [HTTP/1.1 500 Internal Server Error]
    {"error":"Cannot invoke \"String.getBytes(java.nio.charset.Charset)\" because \"src\" is null"}
        at __randomizedtesting.SeedInfo.seed([4E419A2BAF324D00:BDBDF77E35715AC2]:0)
        at app//org.opensearch.client.RestClient.convertResponse(RestClient.java:[38](https://github.com/opensearch-project/flow-framework/actions/runs/7597952688/job/20693407835?pr=431#step:5:39)5)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:355)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:330)
        at app//org.opensearch.flowframework.TestHelpers.makeRequest(TestHelpers.java:116)
        at app//org.opensearch.flowframework.TestHelpers.makeRequest(TestHelpers.java:89)
        at app//org.opensearch.flowframework.TestHelpers.makeRequest(TestHelpers.java:78)
        at app//org.opensearch.flowframework.FlowFrameworkRestTestCase.provisionWorkflow(FlowFrameworkRestTestCase.java:3[39](https://github.com/opensearch-project/flow-framework/actions/runs/7597952688/job/20693407835?pr=431#step:5:40))
        at app//org.opensearch.flowframework.rest.FlowFrameworkRestApiIT.testCreateAndProvisionRemoteModelWorkflow(FlowFrameworkRestApiIT.java:219)
  1> [2024-01-20T21:34:03,091][INFO ][o.o.f.r.FlowFrameworkRestApiIT] [testCreateAndProvisionRemoteModelWorkflow] before test

[joshpalis]

Closing in favor of #432