Do not forcibly log out user if user retrieval fails with a server error code

[bdach]

• Depends on Add property to retrieve status code of a web request osu-framework#6716

This behaviour caused users to get forcibly logged out of the game during yesterday's redis outage.

From one case where logs were provided:

• User had repeated timeouts on API requests; consequently, API went into failing state

• On one of the login retries /api/v2/me returned a 500 with no error details ({"error":null} JSON response) which resulted in an instant logout as per

  osu/osu.Game/Online/API/APIAccess.cs

  Lines 323 to 324 in 7263551

  	log.Add($@"Login failed for username {ProvidedUsername} on user retrieval ({LastLoginError.Message})!");
  	Logout();

This PR intends to only forcibly log the user out if the returned error code indicates a client error. If it is a server error, the login is preserved and a normal retry loop proceeds.

This can be tested with a local web instance via following steps:

1. Start osu-web and a client instance connected to it.
2. Log in on the client instance.
3. Kill (^C) osu-web.
4. Trigger a few requests in the client and wait for enough of them to fail for the API to change to Failing state.
5. Apply

diff --git a/app/Http/Controllers/UsersController.php b/app/Http/Controllers/UsersController.php
index db34639abf2..392a844882a 100644
--- a/app/Http/Controllers/UsersController.php
+++ b/app/Http/Controllers/UsersController.php
@@ -581,6 +581,8 @@ class UsersController extends Controller
      */
     public function me($mode = null)
     {
+        abort(500);
+
         $user = \Auth::user();
         $currentMode = $mode ?? $user->playmode;

6. Start osu-web again.
7. On master this will log the user out forcibly. On this PR, the user will remain in Failing state.
8. Undo patch from step (5) (restarting web is not required).
9. On this PR, the client will be logged back in.

Of particular note, if in the above scenario you apply an abort(403) or similar in step (5), the user will still get forcibly logged out.

[peppy]

test