[Stack Monitoring] baseline logstash api tests for package and metric…

…beat data (elastic#152575)

## Summary

Closes elastic#151158
Part of elastic#148303

Port logstash tests to the
[monitoring_api_integration](https://github.com/elastic/kibana/tree/main/x-pack/test/monitoring_api_integration)
suite. This reimplements all the existing tests (plus missing ones for
the pipeline api) with fresh data.

See [flaky test
run](https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/1982)

x-pack/test/api_integration/apis/monitoring/logstash/index.js

@@ -8,14 +8,9 @@
 export default function ({ loadTestFile }) {
   describe('Logstash', () => {
     loadTestFile(require.resolve('./overview'));
-    loadTestFile(require.resolve('./overview_mb'));
     loadTestFile(require.resolve('./nodes'));
-    loadTestFile(require.resolve('./nodes_mb'));
     loadTestFile(require.resolve('./node_detail'));
-    loadTestFile(require.resolve('./node_detail_mb'));
     loadTestFile(require.resolve('./multicluster_pipelines'));
-    loadTestFile(require.resolve('./multicluster_pipelines_mb'));
     loadTestFile(require.resolve('./pipelines'));
-    loadTestFile(require.resolve('./pipelines_mb'));
   });
 }