Check whether entry is of type ICacheEntry in Cache->remove()

Check whether entry is of type ICacheEntry in Cache->remove()

In some scenarios (file not in cache, but partial data of it in the
object), Cache->get() might return an array, which leads to errors like
"Call to a member function getId() on array".

So check whether the returned entry is of type ICacheEntry before doing
operations on it in Cache->remove().

Fixes: #33023
Signed-off-by: Jonas <jonas@freesources.org>