Remove MasterServiceTests from retries (opensearch-project#8984)

After the fix in opensearch-project#8901, I ran the following in a loop all day (about
1400 times) and saw no failures:

```
./gradlew ':server:test' --tests "org.opensearch.cluster.service.MasterServiceTests"
```

Signed-off-by: Andrew Ross <andrross@amazon.com>

build.gradle

@@ -487,7 +487,6 @@ subprojects {
         includeClasses.add("org.opensearch.cluster.metadata.IndexGraveyardTests")
         includeClasses.add("org.opensearch.cluster.routing.MovePrimaryFirstTests")
         includeClasses.add("org.opensearch.cluster.routing.allocation.decider.DiskThresholdDeciderIT")
-        includeClasses.add("org.opensearch.cluster.service.MasterServiceTests")
         includeClasses.add("org.opensearch.common.util.concurrent.QueueResizableOpenSearchThreadPoolExecutorTests")
         includeClasses.add("org.opensearch.gateway.RecoveryFromGatewayIT")
         includeClasses.add("org.opensearch.gateway.ReplicaShardAllocatorIT")