Pass ModelReaderWriterContext in generated TryResolve{Property}Array helpers (#10839)

The `TryResolve{Property}Array` helpers were emitting
`ModelReaderWriter.Write(collection, options)` without the
`ModelReaderWriterContext` argument, breaking AOT-trimmed builds (e.g.
OpenAI) where the context-less overload isn't preserved.

## Changes

- **`ModelReaderWriterOptionsSnippets.cs`**: Added a new
`JsonFormatProperty` snippet that returns the
`ModelReaderWriterOptions.Json` static property.
- **`MrwSerializationTypeDefinition.Dynamic.cs`**: In
`BuildTryResolveArrayMethod`, append
`ModelReaderWriterContextSnippets.Default` to the
`ModelReaderWriter.Write` invocation, mirroring the pattern already used
in `BuildPersistableModelWriteCoreMethodBody` and the XML serialization
path. Also simplified the options argument to use the new
`ModelReaderWriterOptionsSnippets.JsonFormatProperty` snippet instead of
`new ModelReaderWriterOptions("J")`.
- **Test baseline**: Update `PropagateModelListPropertyHelperMethods.cs`
to expect the third argument and the `ModelReaderWriterOptions.Json`
static.

Generated output now matches the rest of the emitter:

```csharp
global::System.BinaryData data = global::System.ClientModel.Primitives.ModelReaderWriter.Write(
    ActiveP1(),
    global::System.ClientModel.Primitives.ModelReaderWriterOptions.Json,
    global::Sample.SampleContext.Default);
```

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jorgerangel-msft <102122018+jorgerangel-msft@users.noreply.github.com>

Author: Copilot

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/MrwSerializationTypeDefinition.Dynamic.cs

@@ -531,7 +531,8 @@ private MethodProvider BuildTryResolveArrayMethod(PropertyProvider property)
             var dataDeclStatement = Declare("data", typeof(BinaryData),
                 Static(typeof(ModelReaderWriter)).Invoke(nameof(ModelReaderWriter.Write), [
                     new InvokeMethodExpression(null, $"Active{property.Name}", []),
-                    New.Instance(typeof(ModelReaderWriterOptions), Literal("J"))
+                    ModelReaderWriterOptionsSnippets.JsonFormatProperty,
+                    ModelReaderWriterContextSnippets.Default
                 ]),
                 out var dataVar);
 

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Snippets/ModelReaderWriterOptionsSnippets.cs

@@ -15,6 +15,7 @@ internal static class ModelReaderWriterOptionsSnippets
         internal static ScopedApi<string> WireFormat => Literal("W");
         internal static ScopedApi<string> JsonFormat => Literal("J");
         internal static ScopedApi<string> XmlFormat => Literal("X");
+        internal static ScopedApi<ModelReaderWriterOptions> JsonFormatProperty => Static(typeof(ModelReaderWriterOptions)).Property(nameof(ModelReaderWriterOptions.Json)).As<ModelReaderWriterOptions>();
         internal static ScopedApi<ModelReaderWriterOptions> InitializeWireOptions => New.Instance(typeof(ModelReaderWriterOptions), Wire).As<ModelReaderWriterOptions>();
     }
 }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/MrwSerializationTypeDefinitions/TestData/DynamicModelSerializationTests/PropagateModelListPropertyHelperMethods.cs

@@ -15,7 +15,7 @@ public partial class DynamicModel
         private bool TryResolveP1Array(out global::System.ClientModel.Primitives.JsonPatch.EncodedValue value)
         {
             value = default;
-            global::System.BinaryData data = global::System.ClientModel.Primitives.ModelReaderWriter.Write(ActiveP1(), new global::System.ClientModel.Primitives.ModelReaderWriterOptions("J"));
+            global::System.BinaryData data = global::System.ClientModel.Primitives.ModelReaderWriter.Write(ActiveP1(), global::System.ClientModel.Primitives.ModelReaderWriterOptions.Json, global::Sample.SampleContext.Default);
             global::System.ClientModel.Primitives.JsonPatch tempPatch = new global::System.ClientModel.Primitives.JsonPatch();
             tempPatch.Set("$"u8, data.ToMemory().Span);
             return tempPatch.TryGetEncodedValue("$"u8, out value);

packages/http-client-csharp/generator/TestProjects/Local/Sample-TypeSpec/src/Generated/Models/DynamicModel.Serialization.cs

@@ -978,7 +978,7 @@ private bool PropagateSet(ReadOnlySpan<byte> jsonPath, JsonPatch.EncodedValue va
         private bool TryResolveListFooArray(out JsonPatch.EncodedValue value)
         {
             value = default;
-            BinaryData data = ModelReaderWriter.Write(ActiveListFoo(), new ModelReaderWriterOptions("J"));
+            BinaryData data = ModelReaderWriter.Write(ActiveListFoo(), ModelReaderWriterOptions.Json, SampleTypeSpecContext.Default);
             JsonPatch tempPatch = new JsonPatch();
             tempPatch.Set("$"u8, data.ToMemory().Span);
             return tempPatch.TryGetEncodedValue("$"u8, out value);