Improve the format in `asset_bundle.dart` (#126229)

Just found these extra intents and the very long line which might be improved.

Related git blame: https://github.com/flutter/flutter/blame/master/packages/flutter/lib/src/services/asset_bundle.dart#L337.

packages/flutter/lib/src/services/asset_bundle.dart

@@ -323,7 +323,10 @@ class PlatformAssetBundle extends CachingAssetBundle {
   @override
   Future<ByteData> load(String key) {
     final Uint8List encoded = utf8.encoder.convert(Uri(path: Uri.encodeFull(key)).path);
-    final Future<ByteData>? future = ServicesBinding.instance.defaultBinaryMessenger.send('flutter/assets', encoded.buffer.asByteData())?.then((ByteData? asset) {
+    final Future<ByteData>? future = ServicesBinding.instance.defaultBinaryMessenger.send(
+      'flutter/assets',
+      encoded.buffer.asByteData(),
+    )?.then((ByteData? asset) {
       if (asset == null) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           _errorSummaryWithKey(key),
@@ -334,9 +337,9 @@ class PlatformAssetBundle extends CachingAssetBundle {
     });
     if (future == null) {
       throw FlutterError.fromParts(<DiagnosticsNode>[
-          _errorSummaryWithKey(key),
-          ErrorDescription('The asset does not exist or has empty data.'),
-        ]);
+        _errorSummaryWithKey(key),
+        ErrorDescription('The asset does not exist or has empty data.'),
+      ]);
     }
     return future;
   }