When running secret-add and secret-set hook commands in same hook context, the created secret resources kept in provider side even the secret-set was failed

[Yang Kelvin Liu]

$ juju exec --unit hello-kubecon/0 'uri=$(secret-add --owner unit foo=unit1); echo $uri; secret-set $uri --label=aaa;'
secret:cd34kcuffbarderrtpj0
creating secrets: secret with label "aaa" already exists

# secret-add created the `cd34kcuffbarderrtpj0-1` in k8s side, but Juju gave up to save metadata in database because we got label conflict.

$ mkubectl -nt1 get secret/cd34kcuffbarderrtpj0-1
NAME TYPE DATA AGE
cd34kcuffbarderrtpj0-1 Opaque 1 7m6s

$ juju show-secret cd34kcuffbarderrtpj0 --reveal
{}
ERROR secret "cd34kcuffbarderrtpj0" not found

Fix: we should delete the `secret/cd34kcuffbarderrtpj0-1` if we cannot save the secret metadata successfully.