Fixes Failing test: Task Manager MGet Claimer Functional Tests.x-pack…

…/test/task_manager_claimer_mget/test_suites/task_manager/migrations·ts - task_manager with mget task claimer migrations 8.5.0 migrates active tasks to set enabled to true (elastic#192463)

Resolves elastic#190454

## Summary

Updated the query to only return tasks. The flakiness was caused by the
query sometimes returning the new `background-task-node` document type
in the TM index. Also saw another flake where the task manager metrics
comparisons weren't returning correctly because the metrics reset, so
increased the metrics reset interval slightly.

Ran flaky test runner 2x200 times successfully:
*
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/6911
*
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/6913

x-pack/test/task_manager_claimer_mget/config.ts

@@ -32,6 +32,7 @@ export default async function ({ readConfigFile }: FtrConfigProviderContext) {
         '--xpack.task_manager.monitored_aggregated_stats_refresh_rate=5000',
         '--xpack.task_manager.ephemeral_tasks.enabled=false',
         '--xpack.task_manager.ephemeral_tasks.request_capacity=100',
+        '--xpack.task_manager.metrics_reset_interval=40000',
         `--xpack.stack_connectors.enableExperimental=${JSON.stringify(['crowdstrikeConnectorOn'])}`,
         ...findTestPluginPaths(path.resolve(__dirname, 'plugins')),
       ],

x-pack/test/task_manager_claimer_mget/test_suites/task_manager/migrations.ts

@@ -24,8 +24,7 @@ export default function createGetTests({ getService }: FtrProviderContext) {
   const ALERT_ID = '0359d7fcc04da9878ee9aadbda38ba55';
   const ACTION_TASK_PARAMS_ID = '6e96ac5e648f57523879661ea72525b7';
 
-  // FLAKY: https://github.com/elastic/kibana/issues/190454
-  describe.skip('migrations', () => {
+  describe('migrations', () => {
     before(async () => {
       await esArchiver.load('x-pack/test/functional/es_archives/task_manager_tasks');
     });
@@ -147,7 +146,9 @@ export default function createGetTests({ getService }: FtrProviderContext) {
           size: 100,
           body: {
             query: {
-              match_all: {},
+              bool: {
+                filter: [{ term: { type: 'task' } }],
+              },
             },
           },
         },
@@ -174,7 +175,9 @@ export default function createGetTests({ getService }: FtrProviderContext) {
           size: 100,
           body: {
             query: {
-              match_all: {},
+              bool: {
+                filter: [{ term: { type: 'task' } }],
+              },
             },
           },
         },
@@ -200,7 +203,13 @@ export default function createGetTests({ getService }: FtrProviderContext) {
           {
             index: '.kibana_task_manager',
             size: 100,
-            body: { query: { match_all: {} } },
+            body: {
+              query: {
+                bool: {
+                  filter: [{ term: { type: 'task' } }],
+                },
+              },
+            },
           },
           { meta: true }
         );
@@ -233,7 +242,13 @@ export default function createGetTests({ getService }: FtrProviderContext) {
           {
             index: '.kibana_task_manager',
             size: 100,
-            body: { query: { match_all: {} } },
+            body: {
+              query: {
+                bool: {
+                  filter: [{ term: { type: 'task' } }],
+                },
+              },
+            },
           },
           { meta: true }
         );