cephadm: replace call_throws with call in command_inspect_image

cephadm: replace call_throws with call in command_inspect_image

Problem:
During the upgrade, when inspecting the new ceph image for the first time, an error is printed to the ceph-mgr log instead of displaying a user-friendly message.

Root cause: During an upgrade, inspect-image is called on each node to check if the target image exists locally before pulling it. This flow, where inspect-image always precedes the pull, occurs on nodes other than the first.

Code Fixes:
1. src/cephadm/cephadm.py:
   Replace call_throws with call in command_inspect_image. call_throws raises a RuntimeError on any non-zero exit code, producing a full traceback in the logs. call returns the exit code instead of raising, so the function exits cleanly with errno.ENOENT when the image is not found.

Fixes: https://tracker.ceph.com/issues/75448
Signed-off-by: Yael Azulay <yazulay@redhat.com>