[Console] Make getTerminalWidth & getTerminalHeight public

Bug fix: no
Feature addition: yes
Backwards compatibility break: no
Fixes the following tickets: ~
Todo: -
License of the code: MIT
Documentation PR: ~

Hey!

This PR updates the visibility of the Application's methods `getTerminalWidth` & `getTerminalHeight` to **public**. This two methods should be accessible as we can need it in our commands to determine the way we display the output. (see #6550)