[Bug Fix] Fix the demo configuration script and remove the admin credential from internal_user.yml

[RyanL1997]

Description

By working with @DarshitChanpura for addressing the following issue:

opensearch-project/opensearch-build#4094 (comment)

We need the initiation of the cluster to be failed once we encountered a failure of our demo configuration script. This PR introduces the method that if we failed to set up a admin credential during the set up of demo configuration script, it will lead to an absent of admin credential section in internal_users.yml, so that the initiation of the cluster will be failed.

• Category (Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation)
  Bug fix
• What is the old behavior before changes and new behavior after changes?
  The cluster initiation will be succeed and keep using the admin:admin credential even if the there is an hard exit on the set up on demo configuration script.

Issues Resolved

• Relate [Security] Demo configuration script requires admin password  opensearch-build#4094
• Relate Demo configuration script requires admin password #3329

Testing

CI

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Merging #3449 (a3fdf3c) into main (7924da1) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #3449      +/-   ##
============================================
- Coverage     64.56%   64.54%   -0.02%     
+ Complexity     3545     3544       -1     
============================================
  Files           269      269              
  Lines         20363    20363              
  Branches       3376     3376              
============================================
- Hits          13147    13143       -4     
- Misses         5525     5529       +4     
  Partials       1691     1691              

see 2 files with indirect coverage changes

[RyanL1997]

Note: the BWC failure is expected due to the release related version changes.

[peternied]

What is broken without this section?

[RyanL1997]

Based on the log:

 - org.opensearch.security.InitializationIntegrationTests.testDefaultConfig
 - org.opensearch.security.InitializationIntegrationTests.testInvalidDefaultConfig
 - org.opensearch.security.TransportUserInjectorIntegTest.testSecurityUserInjection
 - org.opensearch.security.SlowIntegrationTests.testDelayInSecurityIndexInitialization

For example, the test of InitializationIntegrationTests.testDefaultConfig is using the admin admin credential to send out the request:

security/src/test/java/org/opensearch/security/InitializationIntegrationTests.java

Line 287 in 93f79f8

HttpResponse res = rh.executeGetRequest("/_cluster/health", encodeBasicHeader("admin", "admin"));

[peternied]

Does the cluster fail to startup with this change? Could you include what that looks like?

[DarshitChanpura]

We do not want a cluster to start without admin credentials. What do you think about closing this @RyanL1997 ?

[peternied]

@RyanL1997 Since the password change was reverted in 2.11 - lets regroup and figure out how to approach this. I'm going to close out this PR - we can reopen if we need it. Thanks