Remove leftover of #67877

Closes #69313

Author: jimczi

x-pack/plugin/async-search/src/internalClusterTest/java/org/elasticsearch/xpack/search/AsyncSearchActionIT.java

@@ -437,11 +437,8 @@ public void testRemoveAsyncIndex() throws Exception {
         assertThat(newResp.getSearchResponse().getTotalShards(), equalTo(numShards));
         assertThat(newResp.getSearchResponse().getSuccessfulShards(), equalTo(0));
         assertThat(newResp.getSearchResponse().getFailedShards(), equalTo(0));
-        long expirationTime = newResp.getExpirationTime();
 
         // check garbage collection
-        newResp = getAsyncSearch(newResp.getId(), TimeValue.timeValueMillis(1));
-        assertThat(newResp.getExpirationTime(), lessThan(expirationTime));
         ensureTaskNotRunning(newResp.getId());
         ensureTaskRemoval(newResp.getId());
     }