Improve Android back navigation consistency for deep links

Currently, back navigation on Android is inconsistent. When a user navigates to a new location (e.g., a specific chat) via an i.delta.chat link from another chat or a miniapp, the back button ignores the navigation history and forces the user back to the main chat list instead of the previous screen.

Expected behavior

The Android back button should respect the app’s navigation stack. If a user navigates from “Chat A” to “Chat B” via a deep link, pressing “Back” should return the user to “Chat A.”

Actual behavior

The back button prematurely exits the current navigation context and returns the user to the main chat list, forcing them to re-navigate to their previous location.