feat: prevent typing over-long topic names

[ARYPROGRAMMER]

This PR adds the functionality mentioned in the Issue #1218

• It implements a value notifier, adds a listener and creates a function to enforce limit.
• Displays the limit alongside current characters
• Does not change any core functionality and does not break anything else

Demo Video on a real android device:

demo.mp4

[gnprice]

Thanks. Before we can review this PR, it will need (a) tests, and (b) to remove extraneous changes so that the commit is readable. See our README:
https://github.com/zulip/zulip-flutter?tab=readme-ov-file#submitting-a-pull-request

[ARYPROGRAMMER]

Thanks. Before we can review this PR, it will need (a) tests, and (b) to remove extraneous changes so that the commit is readable. See our README: https://github.com/zulip/zulip-flutter?tab=readme-ov-file#submitting-a-pull-request

surely greg, the file was auto formatted thus it happened so. For the tests, I'll just look into it and fix it

[ARYPROGRAMMER]

@gnprice lgtm now , go ahead with the review. Let me know further

[ARYPROGRAMMER]

Thanks. Before we can review this PR, it will need (a) tests, and (b) to remove extraneous changes so that the commit is readable. See our README: https://github.com/zulip/zulip-flutter?tab=readme-ov-file#submitting-a-pull-request

surely greg, the file was auto formatted thus it happened so. For the tests, I'll just look into it and fix it

hey greg any updates?