Apparently, there is nothing called Twitter anymore hence the old Twitter plugins are now deprecated.
Construct 3 officially suggests using the share plugin instead (Till they officially bring the "X" plugins).
Anyway here is the in-built c3 template that can help you with this.
editor.construct.net
Here check how this template use c3's inbuilt share plugins to share screenshot with the message. (It works not just on Twitter but any app)
Edit:
I've seen the "screenshots example" project in construct, but the share function doesn't work - it's always disabled.
The template is written in such a way that the share button is only enabled when the screenshot is taken.