Improve Icons and Sections in the Accounts Sheet

[PSchmiedmayer]

Problem

• The icons in the account sheet are currently a bit inconsistent.
• The sections should all follow a similar formatting with detail views and list style elements instead of accent-color themed buttons.

Solution

• The icons and section elements in the account sheet should follow the UX designs in Spezi Account and the iOS Settings view.
• We might want to add a new gradient to the gray elements used for iOS 26; we might also want to bring this to Spezi Account as well.

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct and Contributing Guidelines