update subscription activation screens

[LukasPaczos]

Task/Issue URL: https://app.asana.com/0/1208671518894266/1208848139000087

Description

Updates the subscription activation screens according to designs, details in the task (and sub-tasks).

Steps to test this PR

Subscription activation screen

• Without subscription active, open subscription activation screen.
  • If you are in the US, open "I Have a Subscription".
  • If you're not in the US, go to Settings -> Subscription Settings -> Already have a subscription, or follow guidelines from https://app.asana.com/0/1207137509162935/1208816938325110/f.
  • Make sure design matches in light and dark modes.
  • Make sure adding via email opens the FE activation flow.

Subscription settings screen

• With subscription active, open subscription settings screen.
  • Make sure that clicking Add to Device opens the FE activation flow.

UI changes

Subscription activation screen

Before	After

Subscription settings screen (I haven't re-taken screenshots for dark mode)

Before	After