chore: Improved error handling for recovery key

lib/pages/bootstrap/bootstrap_dialog.dart

@@ -266,6 +266,7 @@ class BootstrapDialogState extends State<BootstrapDialog> {
                         ),
                         hintText: L10n.of(context)!.recoveryKey,
                         errorText: _recoveryKeyInputError,
+                        errorMaxLines: 2,
                       ),
                     ),
                     const SizedBox(height: 16),
@@ -290,6 +291,7 @@ class BootstrapDialogState extends State<BootstrapDialog> {
                                 final key = _recoveryKeyTextEditingController
                                     .text
                                     .trim();
+                                if (key.isEmpty) return;
                                 await bootstrap.newSsssKey!.unlock(
                                   keyOrPassphrase: key,
                                 );
@@ -317,6 +319,11 @@ class BootstrapDialogState extends State<BootstrapDialog> {
                                   () => _recoveryKeyInputError =
                                       e.toLocalizedString(context),
                                 );
+                              } on FormatException catch (_) {
+                                setState(
+                                  () => _recoveryKeyInputError =
+                                      L10n.of(context)!.wrongRecoveryKey,
+                                );
                               } catch (e, s) {
                                 ErrorReporter(
                                   context,

lib/pages/homeserver_picker/homeserver_picker.dart

@@ -163,15 +163,16 @@ class HomeserverPickerController extends State<HomeserverPicker> {
   List<IdentityProvider>? get identityProviders {
     final loginTypes = _rawLoginTypes;
     if (loginTypes == null) return null;
-    final List? rawProviders = loginTypes.tryGetList('flows')!.singleWhere(
-              (flow) => flow['type'] == AuthenticationTypes.sso,
-            )['identity_providers'] ??
-        [
-          {'id': null},
-        ];
-    final list = (rawProviders as List)
-        .map((json) => IdentityProvider.fromJson(json))
-        .toList();
+    final List? rawProviders =
+        loginTypes.tryGetList('flows')?.singleWhereOrNull(
+                  (flow) => flow['type'] == AuthenticationTypes.sso,
+                )['identity_providers'] ??
+            [
+              {'id': null},
+            ];
+    if (rawProviders == null) return null;
+    final list =
+        rawProviders.map((json) => IdentityProvider.fromJson(json)).toList();
     if (PlatformInfos.isCupertinoStyle) {
       list.sort((a, b) => a.brand == 'apple' ? -1 : 1);
     }