fix(clippy): apply auto-fixable linting suggestions

useragent/lib/features/identity/pk_manager.dart

@@ -1,11 +1,11 @@
-// The API to handle without storing the private key in memory.
-//The implementation will use platform-specific secure storage and signing capabilities.
-abstract class KeyHandle {
-  Future<List<int>> sign(List<int> data);
-  Future<List<int>> getPublicKey();
-}
-
-abstract class KeyManager {
-  Future<KeyHandle?> get();
-  Future<KeyHandle> create();
-}
+// The API to handle without storing the private key in memory.
+//The implementation will use platform-specific secure storage and signing capabilities.
+abstract class KeyHandle {
+  Future<List<int>> sign(List<int> data);
+  Future<List<int>> getPublicKey();
+}
+
+abstract class KeyManager {
+  Future<KeyHandle?> get();
+  Future<KeyHandle> create();
+}