[Cashtab] Lose the one address format reminder

Summary: Was planning to remove this a long time ago but forgot about it

Test Plan:
@bot preview-cashtab
Navigate to receive screen
Confirm the notice is not there

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13783