Fixes#15285
This event will be used more now for guest users when moving
topic between streams (See #15277). So, instead of deleting
messages in the topic as part of different events which is
very slow and a bad UX, we now handle the messages to delete in
bulk which is a much better UX.
We now use the real implementation of
`stream_data` in our tests (as well as `people`),
while still just checking stubs for "heavier"
functions that we dispatch to.
Also, we use our regular blueslip helpers.
These are basically shims for some deeper refactorings.
I basically just try to make the code express the
problems more clearly:
- use stream_name instead of sub
- make early-exit more explicit
- make it clear that add_subscriber needlessly
requires a name
- make it clear we have an unnecessary loop
I also fixed some phony data in the test.
Aman Agrawal
Steve Howell