Previously this dropdown was only for selecting streams, but
soon it will also be for switching to a private message. This
name helps it be clearer that the dropdown is more general
purpose.
We now show a banner on opening the compose box and changing the
stream in dropdown, if a user is not allowed to post in a stream.
The "Send" button is also disabled if user is not allowed to post
in the stream.
This commit also moved the CSS for disabled modal button in dark
theme below after the other CSS for modals as we are using the
same CSS for the "Send" button as well in disabled state.
We now show all the streams, even if user is not allowed to post
in them, in the stream dropdown in compose box. In further commits,
we would add a banner mentioning that user is not allowed to post
for such streams.
We should trigger click event to open up the dropdown popup instead of using
`.dropdown("toggle")` because we want to clear the search state when opening up
the popup and the logic for that is registered in `on-click` handler defined in
`dropdown_list_widget`.
Fixes: #25218
This helps reduce the amount of import cycles we have in the compose
code path following the migration to a fancier stream input.
`compose_closed_ui.initialize()` was moved further down in the
initialization order because it relies on the dropdown widget
to be defined.