[FS-1191] List the MLS Self-conversation Automatically

[mdimjasevic]

Automatically list the MLS self-conversation in conversation-listing endpoints:

• POST /conversations/list-ids

Tracked by https://wearezeta.atlassian.net/browse/FS-1191.

Checklist

• Make the change only to v3 of the POST /conversation/list-ids endpoint
• Add a new entry in an appropriate subdirectory of changelog.d
• Read and follow the PR guidelines

[smatting]

The deprecated GET /conversations/ids list-conversation-ids-unqualified endpoint is not updated by this PR.
Rather than also updating it maybe we can remove it for V3 in this PR?

[mdimjasevic]

The deprecated GET /conversations/ids list-conversation-ids-unqualified endpoint is not updated by this PR. Rather than also updating it maybe we can remove it for V3 in this PR?

Those two old endpoints are not even touched by this PR, are they? And I'd say that given the scope of this ticket (only the list-ids endpoint) your suggestion should make for a separate PR.

[smatting]

Those two old endpoints are not even touched by this PR, are they? And I'd say that given the scope of this ticket (only the list-ids endpoint) your suggestion should make for a separate PR.

I'm suggesting that the scope of the ticket is not big enough. If we don't update both endpoints together they are inconsistent: that sure can't be right.