DAOS-18239 test: DO NOT LAND exclude PS leader targets

[kccain]

Choose ps leader engine rank in dmg pool exclude command while testing test_osa_online_reintegration_with_multiple_ranks, to see if that case may have an impact on a pool_discard() hang on that engine.

Test based on commit 0ef5142 (latest master).

Test-tag: OSAOnlineReintegration,test_osa_online_reintegration_with_multiple_ranks
Test-Repeat: 10
Skip-unit-tests: true
Skip-fault-injection-test: true
Skip-test-rpms: true
Test-provider-hw-medium: ofi+tcp

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'osa/online_reintegration.py:OSAOnlineReintegration.test_osa_online_reintegration_with_multiple_ranks - dmg: rank 5 failed on pool TestPool_1'
Status is 'In Progress'
Labels: '2.8.0tb1,ci_master_provider,daily_test'
https://daosio.atlassian.net/browse/DAOS-18239