settings: Add option to disable seeing typing notifications.

[roanster007]

This PR adds an option to the advanced section of Preferences settings, that would allow users to choose whether or not to receive typing notifications from other users.

Fixes: #29642

Screenshots and screen captures:

Self-review checklist

• Self-reviewed the changes for clarity and maintainability
  (variable names, code reuse, readability, etc.).

Communicate decisions, questions, and potential concerns.

• Explains differences from previous plans (e.g., issue description).
• Highlights technical choices and bugs encountered.
• Calls out remaining decisions and concerns.
• Automated tests verify logic where appropriate.

Individual commits are ready for review (see commit discipline).

• Each commit is a coherent idea.
• Commit message(s) explain reasoning and motivation for changes.

Completed manual review and testing of the following:

• Visual appearance of the changes.
• Responsiveness and internationalization.
• Strings and tooltips.
• End-to-end functionality of buttons, interactions and flows.
• Corner cases, error conditions, and easily imagined bugs.

[zulipbot]

Hello @zulip/server-settings members, this pull request was labeled with the "area: settings (user)" label, so you may want to check it out!

[timabbott]

This looks basically good; had some comments on API documentation and started a naming thread in https://chat.zulip.org/#narrow/stream/378-api-design/topic/Disabling.20showing.20typing.20notifications/near/1779758.

Generally whenever you're starting an API change project, you should start an "api design" thread about what to call the thing, since it's a detail that should always be chosen carefully. (Unlike most other names, they're a pain to change).

[timabbott]

This looks basically good pending a final decision on renaming the field, and any other API details.

[roanster007]

updated to use receives_typing_notifications

[timabbott]

If we aren't sorting these parameters, it would probably be best to put this next to the others related to typing notifications. But maybe it's worth just doing a follow-up PR to sort the parameters both here and in zerver/views/realm.py; one less thing to make decisions about will be helpful.

[timabbott]

Moved this to be next to the other typing settings in this file for better readability.

[timabbott]

These changes entries should appear in all the places in this file that the field is mentioned -- it looks like it's missing in a couple places.

[timabbott]

Merged, after fixing the small details noted above, thanks @roanster007! I'd appreciate your doing a follow-up PR to sort the keyword argument settings fields as noted above, and maybe the similar one in update_realm; maybe also passing * to indicate the boundary with kwargs might be helpful:

def update_realm(                                                                                       
    request: HttpRequest,                                                                               
    user_profile: UserProfile,                                                                          
    *,
     ...