Rename "provison 1st cluster "title to adjust to reality

[pipo02mix]

Coming from https://github.com/giantswarm/docs/pull/2279#discussion_r1730860729

What this PR does / why we need it

Things to check/remember before submitting

• If you made content changes

  • Run make lint dev to render and proofread content changes locally.
  • Bump last_review_date in the front matter header if you reviewed the entire page.

[pipo02mix]

going ahead to unblock other merge since this a small fix