Remove SessionData.needsVerification as the source of truth for session verification status (#2748)

* Remove `SessionData.needsVerification` as the source of truth for session verification status.

- Use the Rust SDK `EncryptionService.verificationState()` instead, but always waiting for the first 'known' result (either verified or not, discarding 'unknown').
- Add a workaround in the super rare case when reading this value gets stuck somehow. We'll assume the user is not verified in that case.
- Make `DefaultFtueService.getNextStep` and dependent checks `suspend`.
- Make the `skip` button use a value in the session preferences instead.

* Log exception when the verification status can't be loaded

Co-authored-by: Benoit Marty <benoit@matrix.org>

* Fix review comments

---------

Co-authored-by: Benoit Marty <benoit@matrix.org>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/verification/SessionVerificationService.kt

@@ -21,17 +21,6 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.StateFlow
 
 interface SessionVerificationService {
-    /**
-     * This flow stores the local verification status of the current session.
-     *
-     * We should ideally base the verified status in the Rust SDK info, but there are several issues with that approach:
-     *
-     * - The SDK takes a while to report this value, resulting in a delay of 1-2s in displaying the UI.
-     * - We need to add a 'Skip' option for testing purposes, which would not be possible if we relied only on the SDK.
-     * - The SDK sometimes doesn't report the verification state if there is no network connection when the app boots.
-     */
-    val needsVerificationFlow: StateFlow<Boolean>
-
     /**
      * State of the current verification flow ([VerificationFlowState.Initial] if not started).
      */
@@ -83,11 +72,6 @@ interface SessionVerificationService {
      * Returns the verification service state to the initial step.
      */
     suspend fun reset()
-
-    /**
-     * Saves the current session state as [verified].
-     */
-    suspend fun saveVerifiedState(verified: Boolean)
 }
 
 /** Verification status of the current session. */