Fix address book screen

[Radiokot]

Purpose

Fix address book screen after the redesign.

Changes

• Fix crash when opening the address book from the More screen
• Do not show the Continue button if not selecting a recipient

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.