feat(evm): add wallet access grant/revoke functionality

useragent/lib/providers/sdk_clients/wallet_access.dart

@@ -0,0 +1,25 @@
+
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/providers/connection/connection_manager.dart';
+import 'package:mtcore/markettakers.dart';
+import 'package:protobuf/well_known_types/google/protobuf/empty.pb.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'wallet_access.g.dart';
+
+@riverpod
+Future<List<SdkClientWalletAccess>?> walletAccess(Ref ref) async {
+  final connection = await ref.watch(connectionManagerProvider.future);
+  if (connection == null) {
+    return null;
+  }
+
+  final accesses = await connection.ask(UserAgentRequest(listWalletAccess: Empty()));
+
+  if (accesses.hasListWalletAccessResponse()) {
+    return accesses.listWalletAccessResponse.accesses.toList();
+  } else {
+    talker.warning('Received unexpected response for listWalletAccess: $accesses');
+    return null;
+  }
+}