feat(curriculum): add Block 12 of the B1 stage of the English Curriculum

[DanielRosa74]

Checklist:

• [X] I have read and followed the contribution guidelines.
• [X] I have read and followed the how to open a pull request guide.
• [X] My pull request targets the main branch of freeCodeCamp.
• [X] I have tested these changes either locally on my machine, or Gitpod.