4c8ff6f220
When setting any secrets via D-Bus' Update2 call, then
it assumes that all settings are reset. That means, when
we modify any secrets in the client, we need to first load
them all.
Anyway, load always all secrets, then we can also print them
in the get output.
Honor WG_HIDE_KEYS like `wg` does.
(cherry picked from commit 6aa9e52bd8)