[BUG] org.opensearch.upgrades.FullClusterRestartIT > testEmptyShard FAILED

[owaiskazi19]

Describe the bug

REPRODUCE WITH: ./gradlew ':qa:full-cluster-restart:v1.3.0#oldClusterTest' --tests "org.opensearch.upgrades.FullClusterRestartIT.testEmptyShard" -Dtests.seed=3DE5D0AB12901A69 -Dtests.security.manager=true -Dtests.jvm.argline="-XX:TieredStopAtLevel=1 -XX:ReservedCodeCacheSize=64m" -Dtests.locale=ar-AE -Dtests.timezone=America/Dawson -Druntime.java=17

org.opensearch.upgrades.FullClusterRestartIT > testEmptyShard FAILED
    org.opensearch.client.WarningFailureException: method [PUT], host [http://[::1]:37365], URI [/test_empty_shard], status line [HTTP/1.1 200 OK]
    {"acknowledged":true,"shards_acknowledged":true,"index":"test_empty_shard"}
        at __randomizedtesting.SeedInfo.seed([3DE5D0AB12901A69:719E0773EEA935FC]:0)
        at app//org.opensearch.client.RestClient.convertResponse(RestClient.java:346)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:320)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:295)
        at app//org.opensearch.test.rest.OpenSearchRestTestCase.createIndex(OpenSearchRestTestCase.java:976)
        at app//org.opensearch.test.rest.OpenSearchRestTestCase.createIndex(OpenSearchRestTestCase.java:956)
        at app//org.opensearch.test.rest.OpenSearchRestTestCase.createIndex(OpenSearchRestTestCase.java:952)
        at app//org.opensearch.upgrades.FullClusterRestartIT.testEmptyShard(FullClusterRestartIT.java:670)

Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[nknize]

This is fixed by this commit

In short, the index.translog.retention.size setting is deprecated and only applied in testEmptyIndex for Legacy 6.x indexes (which are no longer supported in 2.0). This should've been removed #2225 but I missed it.