Sort leading emoji first in channel names to match web

[gnprice]

On the subscriptions / channels page, a user reported that names starting with an emoji are being sorted to the end, while they appear at the beginning in Zulip web.

We should match web's behavior in this respect.

(Eventually we should agree with Zulip web on the full ordering of all channel names. That's #1165 and is out of scope for this issue.)

Implementation

The name isn't the only key that the subscriptions / channels list is sorted by; it's also sorted by the channel's status as pinned and/or muted. The role of pinning and muting should remain unchanged.

This issue applies to everywhere a list of channels appears. That means:

• the inbox page
• the subscription-list page (accessed through the "channel" icon in the bottom nav bar)
• the all-channels page, once implemented: Offer a list of all channels, and a way to subscribe #188

Related issues

This is a scoped-down version of:

• Sort channel names the same way as Zulip web #1165

The full issue will require work upstream before we have a reasonable way to implement it. This issue is a smaller version that we can do sooner and will help some use cases.

[lakshya1goel]

Hello, I want to work on this issue.

Before	After

My approach sorts the list so that names starting with emojis appear first, followed by non-emoji names sorted alphabetically. To determine if a name starts with an emoji, it checks if the first character falls within specific Unicode ranges representing emoji characters.

Also want a clarification regarding the position of channel names start with some special character like in above example #new_stream_test. Its an inactive channel so in zulip web it appears below the active channels but in zulip-flutter there is no classification for active and inactive channels.

[chrisbobbe]

Thanks! That sounds like a good direction. Please open a PR when your work is ready for review.

in zulip-flutter there is no classification for active and inactive channels.

We can ignore this distinction until we get to #1101, which is planned for a later milestone than this issue.

[lakshya1goel]

Hello, I have raised a PR for this issue. Please have a look on it. Let me know if anything else is required.
Thanks!