Remove active parameter from do_create_user().

Almost all callers to do_create_user were trying to
create active users, except for one test.  The
active=False codepath was kind of broken (things
like sending welcome messages had sort of undefined
behavior there), so instead of trying to maintain it,
we just update the one test (`test_people`) to flip the
`is_active` flag manually.

Fixes #7197

zerver/tests/test_users.py

@@ -438,7 +438,6 @@ class RecipientInfoTest(ZulipTestCase):
             realm=realm,
             full_name='',
             short_name='',
-            active=True,
             bot_type=UserProfile.EMBEDDED_BOT,
         )
 
@@ -459,7 +458,6 @@ class RecipientInfoTest(ZulipTestCase):
             realm=realm,
             full_name='',
             short_name='',
-            active=True,
             bot_type=UserProfile.DEFAULT_BOT,
         )