Collapsable messages should collapse across days

#### Is your suggestion related to a problem? Please describe.
When I look in low-traffic channels, all I see is a barrage of name changes. I would like to see the last messages that were sent in the channel instead

#### Describe the solution you'd like.
I would like all the name changes to collapse into a single line rather than collapsing into one line per day.

#### Describe alternatives you've considered.
I assume that the only alternative is to scroll up every time I open the channel.

#### Additional context
Here's an example of what I'm talking about:

No implementation file or test is named. Start by locating the client code that groups and collapses name-change messages, then inspect how day boundaries are applied. Done means consecutive name changes collapse into one line across day boundaries while ordinary messages remain visible and existing tests pass.

Written by the indexing model from the issue text.