Complete verification links and preserve verified login email (#60)

frontend/packages/sxchnge_auth/lib/src/providers/verification.dart

@@ -35,7 +35,11 @@ class VerificationProvider extends ChangeNotifier {
     try {
       final result = await operation();
       if (_disposed || generation != _generation) return;
-      _state = VerificationState(success, isSimulated: result.isSimulated);
+      _state = VerificationState(
+        success,
+        isSimulated: result.isSimulated,
+        result: success == VerificationStatus.verified ? result : null,
+      );
     } catch (error) {
       if (_disposed || generation != _generation) return;
       final code = error is VerificationException