Reskin remaining settingsV2 components

Summary

Make the rest of the legacy settingsV2 components look more like the rest of settingsV2.

Also added new 'autoplay videos' checkbox to the account section. Everyone can see it but the save button is only enabled for Plus users.

Closes #2683 (closed) #2680 (closed) #2682 (closed)

Steps to test

Try to break & check for responsiveness:

• settings/canary
  • /other
    • /paywall-preview
    • /subscription-tiers
    • /blocked-channels
    • /reported-content
      • /strikes
  • /billing
    • /payment-methods
    • /recurring-payments

Recurring payments is especially rough. 2FA will be in a separate MR.

Found the following issues in the process: #2725 (closed) #2724 (closed) #2708 (closed)

Estimated Regression Scope

• forms not saving properly