This is valuable so that one is forced to explicitly make a decision
on what is correct when adding new callers. Past experience tells us that
not having to explicitly show the decision leads to people introducing
security bugs in PRs that the maintainer has to catch in review, and our
goal for access control code should be that security bugs are hard to write.
Fixes#33688.
Adds an API endpoint for accessing read receipts for other users, as
well as a modal UI for displaying that information.
Enables the previously merged privacy settings UI for managing whether
a user makes read receipts data available to other users.
Documentation is pending, and we'll likely want to link to the
documentation with help_settings_link once it is complete.
Fixes#3618.
Co-authored-by: Tim Abbott <tabbott@zulip.com>
