Display of starred and unstarred messages enhanced

[Dishti-Oberai]

What does this PR do?
This PR enhances the display of consecutive starred and/or unstarred messages which have identical dates, times, and authors.
Earlier all such messages which had similar star status (whether starred or unstarred) appeared together and messages which had different star status were separated by a line. However, this led to difficulty in identifying the star status of messages (which were starred and thus appeared together). The following screenshot depicts the same-

Now, all starred messages and messages which have different star statuses have been separated by a blank line whereas those which are all unstarred appear together. This leads to a better visual display and interpretation of the star status of messages.
The following screenshot demonstrates the present scenario-

(The first two messages are starred and the third one is unstarred in both the above screenshots)

Fixes #171

A detailed explanation of the issue and discussion related to it can be read at - https://chat.zulip.org/#narrow/stream/206-zulip-terminal/topic/Message.20merging.20-.20star.20status.20.28issue.20.23T171.29

Tested?

• Manually
• Existing tests (adapted, if necessary)

Notes & Questions
Should any other changes be made?

Interactions
The changes have been made (developed on) in addition to the following PR - #335

Visual changes
Earlier-

Presently-

[zulipbot]

Hello @Dishti-Oberai, it seems like you have referenced #171 in your pull request description, but you have not referenced them in your commit message description(s). When you reference an issue in a commit message, it automatically closes the corresponding issue when the commit is merged.

Please run git commit --amend in your command line client to amend your commit message description with Fixes #171..

An example of a correctly-formatted commit:

commit fabd5e450374c8dde65ec35f02140383940fe146
Author: zulipbot
Date:   Sat Mar 18 13:42:40 2017 -0700

    pull requests: Check PR commits reference when issue is referenced.

    Fixes #51.

Thank you for your contributions to Zulip!

[neiljp]

@Dishti-Oberai I've marked this as awaiting update, since I assume you're still working on tests.

[Dishti-Oberai]

Thanks for reminding me regarding this @neiljp !
I am working on it presently but it might take some time as I have exams upcoming at my institute too :)
Will try my level best to complete this at the earliest.

[Dishti-Oberai]

@zulipbot add "PR needs review"

[neiljp]

@Dishti-Oberai I left comments in the stream.

The test changes so far make the tests pass, but they don't yet cover the behavior, which is why I can change the new logic and still get the tests to pass.

[zulipbot]

Heads up @Dishti-Oberai, we just merged some commits that conflict with the changes you made in this pull request! You can review this repository's recent commits to see where the conflicts occur. Please rebase your feature branch against the upstream/main branch and resolve your pull request's merge conflicts accordingly.