CSPL-4006: Replication port issue fix

[gabrielm-splunk]

Description

The issue seemed to be that when customers use DefaultsURL or ConfigMap-based defaults, they rely entirely on those sources for replication port config, and if there's any timing issue, parsing problem, or configuration error in the user-provided defaults, the replication port won't be set, causing pod startup failures. This is due to the ordering of how we are checking for our default configuration

The replication_port config was missing from operator-managed default.yml. This would cause IndexerCluster pods to fail with "need to specify replication port".

This seemed to be a quite simple way to address this issue, and since 9887 is the designated default Splunk replication port, seemed to make sense to include as a part of the default config. Open to discussion on potential better solutions to this, however.

Key Changes

This proposed change is as minimal as I could think to do. Port 9887 is the designated default Splunk replication_port, so this seemed to be a reasonable add to the default.yaml that we create.

Testing and Verification

Was able to replicate issue locally and verified this fix can work.

Related Issues

• Jira issue: https://splunk.atlassian.net/browse/CSPL-4006
• Team discussion: https://splunk.slack.com/archives/C07DE987ALF/p1757664970912129

PR Checklist

• Code changes adhere to the project's coding standards.
• Relevant unit and integration tests are included.
• Documentation has been updated accordingly.
• All tests pass locally.
• The PR description follows the project's guidelines.

[coveralls]

Pull Request Test Coverage Report for Build 19516727523

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 86.554%

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Totals
Change from base Build 19427516711:	0.02%
Covered Lines:	10711
Relevant Lines:	12375

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 19516727526

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 86.554%

---

Totals
Change from base Build 19427516711:	0.02%
Covered Lines:	10711
Relevant Lines:	12375

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💛 - Coveralls

[gabrielm-splunk]

As per team discussion, implementing fix on splunk-ansible side