DAOS-19448 test: Fix skip list for release/2.8

[phender]

Use the CI-skip-list-release-2.8 for tests running on the release/2.8 branch.

Test-tag-hw-medium-md-on-ssd: pr test_rebuild_31 test_rebuild_32
skip-functional-hardware-medium-verbs-provider-md-on-ssd: true
skip-functional-hardware-large-md-on-ssd: true

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 'Fix skip list for release/2.8'
Status is 'In Review'
https://daosio.atlassian.net/browse/DAOS-19448

[daosbuild3]

Test stage Functional on EL 9 completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18845/1/execution/node/948/log

[daosbuild3]

Test stage Functional Hardware Medium MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18845/1/execution/node/1173/log

[phender]

Confirmed test_rebuild_31 & 32 and running in https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos/job/PR-18845/2/artifact/Functional%20Hardware%20Medium%20MD%20on%20SSD/daos_test/rebuild.py/results.html using the /CIShare/CI-skip-list-release-2.8 skip list