chore: Add empty environment to mocks (#7294)

It's helpful to have the empty environment in mock data as this is a default value when no environment is set and often needs to be handled differently

bin/load-mocks

@@ -57,6 +57,7 @@ ENVIRONMENTS = itertools.cycle([
     'staging',
     'alpha',
     'beta',
+    ''
 ])
 
 
@@ -76,6 +77,7 @@ def create_sample_event(*args, **kwargs):
             features.record([event])
             return event
 
+
 def generate_commits(user):
     commits = []
     for i in range(random.randint(0, 20)):