test-api: Make desdemona consenting to private data export.

Fixes CI - it was failing due to the API test for organization exports,
which was returning an error due to there being no Organization Owners
with consent to private data export.

(cherry picked from commit e31dfebc07)

tools/test-api

@@ -37,6 +37,7 @@ with test_server_running(
         do_deactivate_realm,
         do_reactivate_realm,
     )
+    from zerver.actions.user_settings import do_change_user_setting
     from zerver.actions.users import change_user_is_active
     from zerver.lib.test_helpers import reset_email_visibility_to_everyone_in_zulip_realm
     from zerver.models.groups import NamedUserGroup, SystemGroups
@@ -87,6 +88,8 @@ with test_server_running(
     realm = get_realm("zulip")
     user = get_user(email, realm)
 
+    do_change_user_setting(user, "allow_private_data_export", True, acting_user=user)
+
     api_key = user.api_key
     site = "http://zulip.zulipdev.com:9981"
     owner_client = Client(