ci: remove pylibssh workaround

Reviewed-by: Jakub Vávra <[email protected]>
(cherry picked from commit 5a800d9)

Author: justin-stephenson

src/tests/system/constraints.txt

@@ -1,8 +1,8 @@
 flaky
 pytest
 git+https://github.com/next-actions/pytest-importance
+git+https://github.com/next-actions/pytest-mh
 git+https://github.com/next-actions/pytest-ticket
 git+https://github.com/next-actions/pytest-tier
 git+https://github.com/next-actions/pytest-output
 git+https://github.com/SSSD/sssd-test-framework
--c constraints.txt