DAOS-19589 pool: Abort extend upon joined ranks

[liw]

Cedric observed a test_osa_dmg_cmd_with_extend failure due to the pool extend operation tolerating ranks already in the pool. Restore the pre-#18651 behavior that aborts such an operation.

Test-tag: Test-tag: pr rebuild OSADmgNegativeTest

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/dmg_negative_test.py:OSADmgNegativeTest.test_osa_dmg_cmd_without_extend- pool reintegration rank is stating OK without pool exclude the rank '
Status is 'In Progress'
Labels: 'ci_master_daily'
https://daosio.atlassian.net/browse/DAOS-19589

[daosbuild3]

Test stage Functional Cluster Box Medium MD on SSD completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-19106/2/testReport/