Fix Bug#29575

Fix Bug#29575

* lisp/net/secrets.el (secrets-create-item): The new item does not
need a unique label.
(secrets-item-path, secrets-get-secret, secrets-get-attributes)
(secrets-get-attribute, secrets-delete-item): ITEM can also be an
object path.  (Bug#29575)

* test/lisp/net/secrets-tests.el (secrets-test03-items):
Test also creation of two items with same label.  Test
`secrets-get-secret', `secrets-get-attribute' and
`secrets-get-attributes' with object path.
(secrets-test04-search): Harden test.