Add OIDC event to allow caller to react to OIDC PAR failure during challenge phase

Description

Add new OIDC OnPushAuthorizationFailed, new context for this event, logic to fire event, tests.

Problem

When a validation failure occurs during a PAR request (ex. the request includes an invalid client_id), an OpenIdConnectProtocolException is thrown. This exception bubbles up as an unhandled middleware exception.

Please see issue #59462 for slightly more details.

Goal

We need to give the application the ability to handle the response when a PAR request fails during the challenge phase. Since an exception during the challenge phase bubbles up as a middleware exception, it is difficult for the application to respond. By including a specific OIDC event, the application has the opportunity to redirect the browser to a user-friendly error page.

Example of a web app utilizing this new feature

builder.Services.AddAuthentication(...)
  .AddOpenIdConnect("oidc", options => 
  {
    ...
    options.Events.OnPushAuthorizationFailed = (ctx) => {
        var logger = ctx.HttpContext.RequestServices.GetRequiredService<ILogger<Program>>();
        logger.LogError(ctx.Exception, "Received error while sending PAR request.");
        
        ctx.Response.Redirect("FriendlyErrorPage");
        ctx.Handled = true;
        return Task.CompletedTask;
    };
  });

Fixes #59462