Use Backchannel.DefaultRequestVersion in OAuth & OIDC requests #20096 (#20295)

Author: huysentruitw

src/Security/Authentication/OAuth/src/OAuthHandler.cs

@@ -196,6 +196,7 @@ protected virtual async Task<OAuthTokenResponse> ExchangeCodeAsync(OAuthCodeExch
             var requestMessage = new HttpRequestMessage(HttpMethod.Post, Options.TokenEndpoint);
             requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
             requestMessage.Content = requestContent;
+            requestMessage.Version = Backchannel.DefaultRequestVersion;
             var response = await Backchannel.SendAsync(requestMessage, Context.RequestAborted);
             if (response.IsSuccessStatusCode)
             {

src/Security/Authentication/OpenIdConnect/src/OpenIdConnectHandler.cs

@@ -806,7 +806,7 @@ protected virtual async Task<OpenIdConnectMessage> RedeemAuthorizationCodeAsync(
 
             var requestMessage = new HttpRequestMessage(HttpMethod.Post, tokenEndpointRequest.TokenEndpoint ?? _configuration.TokenEndpoint);
             requestMessage.Content = new FormUrlEncodedContent(tokenEndpointRequest.Parameters);
-
+            requestMessage.Version = Backchannel.DefaultRequestVersion;
             var responseMessage = await Backchannel.SendAsync(requestMessage);
 
             var contentMediaType = responseMessage.Content.Headers.ContentType?.MediaType;
@@ -869,6 +869,7 @@ protected virtual async Task<HandleRequestResult> GetUserInformationAsync(
             Logger.RetrievingClaims();
             var requestMessage = new HttpRequestMessage(HttpMethod.Get, userInfoEndpoint);
             requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", message.AccessToken);
+            requestMessage.Version = Backchannel.DefaultRequestVersion;
             var responseMessage = await Backchannel.SendAsync(requestMessage);
             responseMessage.EnsureSuccessStatusCode();
             var userInfoResponse = await responseMessage.Content.ReadAsStringAsync();