Description of problem:
Snap Schedule list on invalid path needs to provide command response as an error for invalid path, but it generates a Traceback as below,

[root@ceph-sumar-regression-5ohzjt-node6 ~]# ceph fs snap-schedule list /volumes/svg2/sv1 --fs cephfs
Error EINVAL: Traceback (most recent call last):
  File "/usr/share/ceph/mgr/mgr_module.py", line 1794, in _handle_command
    return CLICommand.COMMANDS[cmd['prefix']].call(self, cmd, inbuf)
  File "/usr/share/ceph/mgr/mgr_module.py", line 462, in call
    return self.func(mgr, **kwargs)
  File "/usr/share/ceph/mgr/snap_schedule/module.py", line 154, in snap_schedule_list
    return -errno.ENOENT, '', f'SnapSchedule for {abs_path} not found'
NameError: name 'abs_path' is not defined

Here, the traceback info generates ambiguous message in "NameError: name 'abs_path' is not defined". The user level error message had to mention the path '/volumes/svg2/sv1' as invalid or something similar to 'Error ENOENT: No schedule found for /volumes/svg2/sv1'

Traceback info needs in command response needs to be avoided and simple error message relevant to non-existing path needs to be printed.

Version-Release number of selected component (if applicable):


How reproducible: consistent