This commit refactors the topic_menu visible check and hide logic,
since we have already migrated the popover from stream_popover.js.
This last bit of code related to topic_menu is also migrated to
popover_menus.js, and the code is refactored to use the new logic,
which is more common for the popover_menus.js system.
To hide the popover, one possible solution could be to use the
hideAll method from TippyJS. However, this could lead to
unintentional behavior for all the popovers. To prevent this, the
hide method is used for the topic_menu only.
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>