Extract send_stream_creation_events_for_private_streams.
Extract send_stream_creation_events_for_private_streams.

We can probably avoid passing in users here.

kou/zulip,zulip/zulip,showell/zulip,eeshangarg/zulip,hackerkid/zulip,zulip/zulip,hackerkid/zulip,kou/zulip,showell/zulip,andersk/zulip,zulip/zulip,punchagan/zulip,rht/zulip,kou/zulip,andersk/zulip,punchagan/zulip,hackerkid/zulip,punchagan/zulip,rht/zulip,eeshangarg/zulip,punchagan/zulip,andersk/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,showell/zulip,showell/zulip,rht/zulip,showell/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,kou/zulip,hackerkid/zulip,rht/zulip,andersk/zulip,showell/zulip,punchagan/zulip,andersk/zulip,kou/zulip,hackerkid/zulip,kou/zulip,hackerkid/zulip,rht/zulip,zulip/zulip,hackerkid/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,rht/zulip,punchagan/zulip,punchagan/zulip,eeshangarg/zulip,zulip/zulip,eeshangarg/zulip