Add media-twitter support to thunder sub-module

Problem

Config for rendering media-twitter was removed when the module was ported to 3.x

Steps to reproduce

Proposed resolution

Re-add suiting config and re-add the testTwitterParagraph() method

see https://git.drupalcode.org/project/custom_elements/-/blob/3.x/tests/src/... and
https://git.drupalcode.org/project/custom_elements/-/blob/3.x/tests/src/...