Fix testCloseOrDeleteIndexDuringSnapshot (#42007)

* This test was resulting in a `PARTIAL` instead of a `SUCCESS` state for
the case of closing an index during snapshotting on 7.x
  * The reason for this is the changed default behaviour regarding
waiting for active shards between 8.0 and 7.x
  * Fixed by adjusting the waiting behaviour on the close index request
in the test
* Closes #39828

server/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java

@@ -2483,7 +2483,7 @@ public void testCloseOrDeleteIndexDuringSnapshot() throws Exception {
                 } else {
                     logger.info("--> close index while partial snapshot is running");
                     closedOnPartial = true;
-                    client.admin().indices().prepareClose("test-idx-1").get();
+                    client.admin().indices().prepareClose("test-idx-1").setWaitForActiveShards(ActiveShardCount.DEFAULT).get();
                 }
             } else {
                 // non-partial snapshots do not allow close / delete operations on indices where snapshot has not been completed