Refactor narrow patterns (use stream ID)

[jainkuniya]

Currently for stream narrow, narrow object is like:

{
operand: "NLP"
operator: "stream"
}

Now the problem is:
What if user is in such narrow and stream name changes? Our getIsActiveStreamSubscribed will start returning false. As we are comparing names

subscriptions.find(sub => narrow[0].operand === sub.name)

How to reproduce:

• Narrow to any stream.
• Change it's name, via Clicking on info button in nav bar in chatScreen.
• Now navigate back to chat screen after changing name.

Observation:

• "Not subscribed" message is displayed instead of ComposeBox.
• NavBar is gray.

Same goes for PM narrow, on changing email.

@gnprice @borisyankov
What should be the priority of this issue?

@zulipbot claim

[borisyankov]

This is not the only issue. We will be trying to fetch more messages for a non-existing narrow too.

[borisyankov]

I think the title of this issue is quite generic and misleading, rename to something that better reflects the problem.

[borisyankov]

ChatScreen needs to have its params.narrow changed.
What we need to do:

if (stream renamed && we are narrowed to it) {
  goBack();
  doNarrow(newStringNarrow);
}

That will be a bit disruptive UI-wise though, but that is fine for a rare occurrence.

[gnprice]

Tracking this now as part of #4333.