Use Octokit.GraphQL instead of Octokit for the performance aspects

According to the GitHubIssueSearchDataSource class, it possibly queries hundreds of issues using Octokit.NET.

https://github.com/microsoft/NativeAOTDependencyHelper/blob/ee7c92ada9c4e7ef6c91e9f5807bf99d462952e0/NativeAOTDependencyHelper.Core/Sources/GitHubIssueSearchDataSource.cs#L66

However, GitHub API v3 (or Octokit or REST API) is not recommended where GitHub API v4 (or Octokit.GraphQL or GraphLQ API) is available since it queries the whole information at the API endpoint even if you don't request.

https://github.com/octokit/octokit.graphql.net

> dotnet add package Octokit.GraphQL

This GraphQL source does a query for a word AOT in the title of issues on CommunityToolkit/Windows.
Try run this in https://docs.github.com/en/graphql/overview/explorer

query
{
    search(
        query: "repo:CommunityToolkit/Windows is:issue in:title AOT",
        type: ISSUE,
        first: 1)
    {
        issueCount
    }
}

var connection = new Connection(new ProductHeaderValue("NativeAOTDependencyHelper"), "ACCESS_TOKEN");

var query = new Query()
    .Search("repo:microsoft/terminal is:issue in:title AOT", SearchType.Issue, first: 1)
    .Select(search => new
    {
        // No other data is queried or returned
        search.IssueCount,
    });

var response = await connection.Run(query);

var issueCount = response.IssueCount;

This is equivalent to:
https://github.com/search?q=repo%3ACommunityToolkit%2FWindows+is%3Aissue+in%3Atitle+AOT&type=issues
if you'd like to change the URL for users to visit:
https://github.com/microsoft/NativeAOTDependencyHelper/blob/ee7c92ada9c4e7ef6c91e9f5807bf99d462952e0/NativeAOTDependencyHelper.Core/Sources/GitHubIssueSearchDataSource.cs#L63

Start in NativeAOTDependencyHelper.Core/Sources/GitHubIssueSearchDataSource.cs around lines 63-66 and inspect how Octokit queries GitHub issues. Compare that call with the provided Octokit.GraphQL example, then verify that the issue-count behavior remains equivalent and that the resulting query requests only the needed data.