client: do not open dir for a non-dir inode

client: do not open dir for a non-dir inode

adds an extra ref to the root which leads to ref leaks:
2025-03-26T15:37:55.162+0530 7fadb8d41640  1 client.4293 dump_inode: DISCONNECTED inode 0x1 #0x1 ref 2 0x1.head(faked_ino=0 nref=2 ll_ref=0 cap_refs={1024=0} open={} mode=41777 size=0/0 nlink=1 btime=2025-03-26T15:37:39.967146+0530 mtime=2025-03-26T15:37:45.113229+0530 ctime=2025-03-26T15:37:45.136266+0530 change_attr=3 caps=pAsLsXs(0=pAsLsXs) COMPLETE has_dir_layout 0x7fad78006970)

which leads to:
2025-03-26T15:37:55.162+0530 7fadb8d41640  2 client.4293 cache still has 1+1 items, waiting (for caps to release?)

Fixes: https://tracker.ceph.com/issues/70553
Signed-off-by: Dhairya Parmar <dparmar@redhat.com>
(cherry picked from commit 23b6b435835a095ceb10de92c3153ec1351d259c)