[Bug]Update/Remove ensure_opensearch_version unit tests that rely on TestScheduler

[boktorbb]

TestScheduler in rxjs seems to cause an oom issue related to:

https://rxjs.dev/guide/testing/marble-testing#known-issues

The following 2 unit tests in ensure_opensearch_version.test.ts have been skipped for now: it.skip('starts polling immediately and then every opensearchVersionCheckInterval' and it.skip('waits for opensearch version check requests to complete before scheduling the next one'

We need to look at either updating or removing the unit tests after some investigation into the issue

[ananzh]

Tried to increase the heap size in both ubuntu and Jenkins env by:

1) Ubuntu: NODE_OPTIONS="--max_old_space_size=8192" yarn test:jest /home/anan/work/OpenSearch-Dashboards/src/core/server/opensearch/version_check/ensure_opensearch_version.test.ts

2) Jenkins Change Jenkinsfile and add env.NODE_OPTIONS = '--max_old_space_size=8192'

Tried size = 8192, 12288, and 16384. None of them work. Need to investigate more. I suggest skip them for GA.