[v2.12.0] Ensure CI/documentation reflect changes to default admin credentials

[DarshitChanpura]

Background

Previously, when installing the security plugin demo configuration, the cluster was spun up with the default admin credentials, admin:admin. A change was made in main and backported to 2.x for the 2.12.0 release, which now requires an initial admin password to be passed in via the environment variable OPENSEARCH_INITIAL_ADMIN_PASSWORD. This will break some CI/testing that relies on OpenSearch to come up without setting this environment variable. This tracking issue is to ensure compliance with the new changes.

Coming from: opensearch-project/security#3624

Acceptance Criteria

• All documentation references to the old default credentials admin:admin are removed
• Ensure that CI/testing is working with main and 2.x branches

[xinyual]

I will take a look.

[xinyual]

Hi @DarshitChanpura , I have checked the current CI logic. ML-commons already generate a random password and set inside environment using -e

ml-commons/.github/workflows/CI-workflow.yml

Line 144 in d0895bb

- name: Generate Password For Admin

. Do you think we need change anymore?

[DarshitChanpura]

Closed as completed in: https://github.com/opensearch-project/ml-commons/pull/1846/files