Bug 1541121: [try-staging] Allow staging release to not have partials; r=aki

We check that partials as a safety check. But we don't need that for staging builds,
and it is often useful to be able to test things that don't depend on partials.

The shipit UI currently still requires partials, but that can be worked around using
the react dev tools.

Differential Revision: https://phabricator.services.mozilla.com/D24834

--HG--
extra : moz-landing-system : lando

taskcluster/taskgraph/actions/release_promotion.py

@@ -24,7 +24,7 @@ from taskgraph.util.partners import (
 from taskgraph.taskgraph import TaskGraph
 from taskgraph.decision import taskgraph_decision
 from taskgraph.parameters import Parameters
-from taskgraph.util.attributes import RELEASE_PROMOTION_PROJECTS
+from taskgraph.util.attributes import RELEASE_PROMOTION_PROJECTS, release_level
 
 
 RELEASE_PROMOTION_SIGNOFFS = ('mar-signing', )
@@ -253,7 +253,7 @@ def release_promotion_action(parameters, graph_config, input, task_group_id, tas
 
     if promotion_config.get('partial-updates', False):
         partial_updates = input.get('partial_updates', {})
-        if not partial_updates:
+        if not partial_updates and release_level(parameters['project']) == 'production':
             raise Exception(
                 "`partial_updates` property needs to be provided for `{}`"
                 "target.".format(release_promotion_flavor)