Fix flakiness in testTimestampPinUnpin

Signed-off-by: Sachin Kale <sachinpkale@gmail.com>

server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStorePinnedTimestampsIT.java

@@ -76,8 +76,6 @@ public void testTimestampPinUnpin() throws Exception {
         );
 
         Tuple<Long, Set<Long>> pinnedTimestampWithFetchTimestamp = RemoteStorePinnedTimestampService.getPinnedTimestamps();
-        long lastFetchTimestamp = pinnedTimestampWithFetchTimestamp.v1();
-        assertEquals(-1L, lastFetchTimestamp);
         assertEquals(Set.of(), pinnedTimestampWithFetchTimestamp.v2());
 
         long timestamp1 = System.currentTimeMillis() + 30000L;