Switch Components E2E manifest generation to DataContractJsonSerializer

[Copilot]

Switch Components E2E manifest generation to DataContractJsonSerializer

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Align Components.Testing.Tasks manifest serialization with MVC.Testing.Tasks by replacing System.Text.Json usage with DataContractJsonSerializer while preserving manifest shape and dictionary formatting.

Description

• Serialization pipeline

  • GenerateE2EManifest now writes manifest JSON via DataContractJsonSerializer + JsonReaderWriterFactory (UTF-8, indented, simple dictionary format).
  • Removed source-generated System.Text.Json context usage from task-side manifest generation.

• Manifest model contract

  • Added [DataContract] / [DataMember(Name = ...)] to task manifest models so emitted JSON property names remain stable (apps, executable, arguments, workingDirectory, publicUrl, environmentVariables).

• Task project dependencies

  • Removed the System.Text.Json reference from Microsoft.AspNetCore.Components.Testing.Tasks.csproj.
  • Deleted obsolete tasks/E2EManifestJsonContext.cs.

var serializer = new DataContractJsonSerializer(typeof(E2EManifestModel), new DataContractJsonSerializerSettings
{
    UseSimpleDictionaryFormat = true,
});
using var writer = JsonReaderWriterFactory.CreateJsonWriter(fileStream, Encoding.UTF8, ownsStream: false, indent: true);
serializer.WriteObject(writer, manifest);

[Copilot]

Pull request overview

This PR updates the Components E2E manifest generation MSBuild task to use DataContractJsonSerializer (matching the approach used in Mvc.Testing.Tasks) instead of System.Text.Json, while preserving the manifest’s JSON shape and dictionary/object formatting expected by existing consumers.

Changes:

• Switched GenerateE2EManifest to write JSON via DataContractJsonSerializer + JsonReaderWriterFactory (UTF-8, indented, simple dictionary format).
• Annotated the task-side manifest model types with [DataContract] / [DataMember(Name = ...)] to keep property names stable.
• Removed the task project’s System.Text.Json reference and deleted the now-obsolete source-generation context file.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/Components/Testing/tasks/Microsoft.AspNetCore.Components.Testing.Tasks.csproj	Drops the explicit System.Text.Json reference now that task-side serialization no longer depends on it.
src/Components/Testing/tasks/GenerateE2EManifest.cs	Replaces System.Text.Json serialization with DataContractJsonSerializer output written directly to the manifest file stream.
src/Components/Testing/tasks/E2EManifestModel.cs	Adds DataContract/DataMember attributes to preserve JSON property names under DataContractJsonSerializer.
src/Components/Testing/tasks/E2EManifestJsonContext.cs	Removes the task-side System.Text.Json source-generation context (no longer used).