Restore response status code in exception messages

[RudeySH]

After updating my SteamKit dependency from 2.1.0 to 2.2.0, I noticed the exception messages from Web API requests were slightly different. Before 2.2.0, an example exception message looked like this:

Response status code does not indicate success: 403 (Forbidden).

But now after updating to 2.2.0, the same message looks like this:

Response status code does not indicate success: Forbidden (Forbidden).

This change was caused by #603 and is most likely unintentional. My pull requests restores the original exception messages.

[codecov]

Codecov Report

Merging #779 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #779      +/-   ##
==========================================
+ Coverage   22.73%   22.77%   +0.04%     
==========================================
  Files          94       95       +1     
  Lines        9311     9329      +18     
  Branches      771      772       +1     
==========================================
+ Hits         2117     2125       +8     
- Misses       7060     7070      +10     
  Partials      134      134

Impacted Files	Coverage Δ
SteamKit2/SteamKit2/Steam/WebAPI/WebAPI.cs	57.79% <100%> (ø)	⬆️
SteamKit2/SteamKit2/Steam/CDNClient.cs	20.23% <100%> (ø)	⬆️
...SteamKit2/Networking/Steam3/NetFilterEncryption.cs	0% <0%> (ø)	⬆️
SteamKit2/SteamKit2/Util/DebugNetworkListener.cs	0% <0%> (ø)	⬆️
...mKit2/SteamKit2/Networking/Steam3/UdpConnection.cs	0% <0%> (ø)	⬆️
...2/Networking/Steam3/NetFilterEncryptionWithHMAC.cs	0% <0%> (ø)	⬆️
...SteamKit2/Networking/Steam3/WebSocketConnection.cs	0% <0%> (ø)	⬆️
...mKit2/SteamKit2/Networking/Steam3/TcpConnection.cs	0% <0%> (ø)	⬆️
SteamKit2/SteamKit2/Util/ILogContext.cs	100% <0%> (ø)
...eamKit2/SteamKit2/Steam/SteamClient/SteamClient.cs	47.08% <0%> (+1.58%)	⬆️

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[yaakov-h]

Thanks!