feat: add option to show command info

Description

This PR adds an option to the Polls for the User to decide whether the footer with the command used to create the Poll should be shown or not. It's false by default. There's also a change from mrkdwn to plain_text to avoid unnecessary padding in the Poll View

Motivation

When creating Polls with large text bodies, the resulting Poll View is very very large and occupies a large portion of the screen (or more than a fullscreen worth of text). This is a little clumsy, as the command isn't really useful to anyone responding to the poll most of the time