mon: MonCap: take EntityName instead when expanding profiles

mon: MonCap: take EntityName instead when expanding profiles

entity_name_t is tightly coupled to the messenger, while EntityName is
tied to auth.  When expanding profiles we want to tie the profile
expansion to the entity that was authenticated.  Otherwise we may incur
in weird behavior such as having caps validation failing because a given
client messenger inst does not match the auth entity it used.

e.g., running

ceph --name osd.0 config-key exists foo daemon-private/osd.X/foo

has entity_name_t 'client.12345' and EntityName 'osd.0'.  Using
entity_name_t during profile expansion would not allow the client access
to daemon-private/osd.X/foo (client.12345 != osd.X).

Fixes: #10844
Backport: firefly,giant

Signed-off-by: Joao Eduardo Luis <joao@redhat.com>