mgr: pin pytest to version 7.4.4

mgr: pin pytest to version 7.4.4

On 2024-01-27, pytest updated to 8.0.0,
which broke run-tox-mgr.

https://docs.pytest.org/en/stable/changelog.html

==================================== ERRORS ====================================
_____________________ ERROR collecting alerts/__init__.py ______________________
alerts/__init__.py:2: in <module>
    from .module import Alerts
alerts/module.py:6: in <module>
    from mgr_module import CLIReadCommand, HandleCommandResult, MgrModule, Option
mgr_module.py:1: in <module>
    import ceph_module  # noqa
E   ModuleNotFoundError: No module named 'ceph_module'
______________________ ERROR collecting alerts/module.py _______________________
alerts/module.py:6: in <module>
    from mgr_module import CLIReadCommand, HandleCommandResult, MgrModule, Option
mgr_module.py:1: in <module>
    import ceph_module  # noqa
E   ModuleNotFoundError: No module named 'ceph_module'
____________________ ERROR collecting balancer/__init__.py _____________________
balancer/__init__.py:2: in <module>
    from .module import Module
balancer/module.py:12: in <module>
    from mgr_module import CLIReadCommand, CLICommand, CommandResult, MgrModule, Option, OSDMap, CephReleases
mgr_module.py:1: in <module>
    import ceph_module  # noqa
E   ModuleNotFoundError: No module named 'ceph_module'
_____________________ ERROR collecting balancer/module.py ______________________
balancer/module.py:12: in <module>
    from mgr_module import CLIReadCommand, CLICommand, CommandResult, MgrModule, Option, OSDMap, CephReleases
mgr_module.py:1: in <module>
    import ceph_module  # noqa
E   ModuleNotFoundError: No module named 'ceph_module'

Fixes: https://tracker.ceph.com/issues/64200
Signed-off-by: Laura Flores <lflores@ibm.com>