Replace RestSharp with HttpClient to eliminate dependency conflicts

[Copilot]

RestSharp dependency causes version conflicts between Dynamo, Revit hosts, and package authors. Migrated to built-in .NET HttpClient.

Changes

HTTP client replacements:

• NodeAutoCompleteSearchViewModel.cs - ML autocomplete API calls (7s timeout via HttpClient.Timeout)
• NodeAutoCompleteBarViewModel.cs - Generic autocomplete API calls with Bearer token auth
• DynamoMLDataPipeline.cs - Data pipeline POST/PUT operations with Bearer token auth
• DynamoPackagesAnalyzer/DynamoPackagesSource.cs - Package download GET requests with async/await

Project references:

• Removed RestSharp package from 7 .csproj files (DynamoCore, DynamoCoreWpf, DynamoMLDataPipeline, DynamoPackages, PackageDetailsViewExtension, NodeDocumentationMarkdownGenerator, DynamoPackagesAnalyzer)

API changes:

• Removed IOAuth2AuthProvider interface implementation from IDSDKManager (interface required RestSharp types)
• Removed IDSDKManager.SignRequest() and IDSDKManager.LoginRequest() methods (unused and required RestSharp types)
• GetAccessToken() from IOAuth2AccessTokenProvider remains as the API for obtaining bearer tokens

Example

Before:

var options = new RestClientOptions(uri) { Timeout = new TimeSpan(0, 0, 7) };
var client = new RestClient(options);
var request = new RestRequest(string.Empty, Method.Post);
request.AddHeader("Authorization", $"Bearer {token}");
request.AddJsonBody(requestJSON);
var response = client.Execute(request);

After:

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri(uri);
    client.Timeout = TimeSpan.FromSeconds(7);
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
    var content = new StringContent(requestJSON, Encoding.UTF8, "application/json");
    var response = await client.PostAsync(string.Empty, content);
}

JSON serialization continues using Newtonsoft.Json for consistency.

Original prompt

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This section details on the original issue you should resolve

<issue_title>How to avoid dependency conflicts of RestSharp version between Dynamo and packages or hosts</issue_title>
<issue_description>### What did you expect to see?

There is no longer RestSharp dependency in Dynamo code base.

Details

Dynamo itself is depending on RestSharp for any RestAPI calls. This requires Dynamo aligning such version with Revit and package authors all the time.

Suggested solution:
Dynamo migrates from RestSharp to HttpClient (Built-in .NET) given HttpClient is the most common built-in replacement for RestSharp.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes How to avoid dependency conflicts of RestSharp version between Dynamo and packages or hosts #16840

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[QilongTang]

@copilot Fix build error IDSDKManager.cs(14,33): error CS0535: 'IDSDKManager' does not implement interface member 'IOAuth2AuthProvider.SignRequest(ref RestRequest, RestClient)'

[Copilot]

@copilot Fix build error IDSDKManager.cs(14,33): error CS0535: 'IDSDKManager' does not implement interface member 'IOAuth2AuthProvider.SignRequest(ref RestRequest, RestClient)'

Fixed in commit 27758e7. Removed IOAuth2AuthProvider interface implementation from IDSDKManager since it required RestSharp types (RestRequest, RestClient). The interface was only checked but never used - code now uses IOAuth2AccessTokenProvider.GetAccessToken() directly. Also completed migration of NodeAutoCompleteBarViewModel.cs to HttpClient.

[QilongTang]

@zeusongit suggested to include Greg in this conversation. I believe the current PR is hitting that point. It does seem that same migration but in Greg would make more sense