Some files already were using `noop` in place of `() => {}`.
It's both clearer what it means and is easier to type.
This updates all test files to fully use `noop`, and
adds a shared import from the test lib file.
This test did extensive mocking and didn't feel like it either fully
tested the module or did a good job of testing the logic; and will
break with the migration to tippy. I think it's better to remove the
test and plan to write a new one testing just
get_user_card_popover_data, the actual interesting part for node tests
of this module.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>