Fix PackageUpgradeTests - v2 (#76259)

Update to #76235
using the correct password this time.

qa/os/src/test/java/org/elasticsearch/packaging/test/PackageUpgradeTests.java

@@ -90,11 +90,11 @@ public void test21CheckUpgradedVersion() throws Exception {
     private void assertDocsExist() throws Exception {
         // We can properly handle this as part of https://github.com/elastic/elasticsearch/issues/75940
         // For now we can use elastic with "keystore.seed" as we set it explicitly in PackageUpgradeTests#test11ModifyKeystore
-        String response1 = makeRequest(Request.Get("http://localhost:9200/library/_doc/1?pretty"), "elastic", "keystore.seed", null);
+        String response1 = makeRequest(Request.Get("http://localhost:9200/library/_doc/1?pretty"), "elastic", "keystore_seed", null);
         assertThat(response1, containsString("Elasticsearch"));
-        String response2 = makeRequest(Request.Get("http://localhost:9200/library/_doc/2?pretty"), "elastic", "keystore.seed", null);
+        String response2 = makeRequest(Request.Get("http://localhost:9200/library/_doc/2?pretty"), "elastic", "keystore_seed", null);
         assertThat(response2, containsString("World"));
-        String response3 = makeRequest(Request.Get("http://localhost:9200/library2/_doc/1?pretty"), "elastic", "keystore.seed", null);
+        String response3 = makeRequest(Request.Get("http://localhost:9200/library2/_doc/1?pretty"), "elastic", "keystore_seed", null);
         assertThat(response3, containsString("Darkness"));
     }
 }