Fix "email changed" activity email check

[julien-nc]

Check disable_activity.email_address_changed_by_admin when email is changed by admin via the OCS API and not just only when set via OCC.

This setting value was never checked if there was an actor (meaning it was done by the API) but if the actor is different than the target user, we can safely assume it is an admin and apply the settings which prevent notifications for this event.

If you want to test that, here are the 2 methods to change a user email address as an admin:
OCC:

occ user:setting USER_ID settings email 'NEW_EMAIL'

OCS API:

curl -H "ocs-apirequest: true" \
    -u ADMIN_USER_ID:ADMIN_PASSWORD \
    -X PUT \
    -d 'key=email&value=URL_ENCODED_NEW_EMAIL' \
    https://my.nc.org/ocs/v1.php/cloud/users/USER_ID

How to toggle the setting:

# DISABLE the notification
occ config:app:set settings disable_activity.email_address_changed_by_admin --value yes
# ENABLE it
occ config:app:set settings disable_activity.email_address_changed_by_admin --value no

With this PR, there is no more email notification when changing the email via the OCS request when the user making the request is different than the target user.

This could be backported to 24 and 23.

[julien-nc]

/backport to stable23

[julien-nc]

/backport to stable24

[julien-nc]

/backport to stable25

[marcelklehr]

Changes make sense ♥️

[julien-nc]

Drone failure is unrelated