Don't return early after re-running checks after startup grace period

Closes #1600

(cherry picked from commit 06464d720c0d31c22865629062d6da0911d2a01f)

src/NzbDrone.Core/HealthCheck/HealthCheckService.cs

@@ -162,8 +162,6 @@ namespace NzbDrone.Core.HealthCheck
                 }
 
                 _isRunningHealthChecksAfterGracePeriod = false;
-
-                return;
             }
 
             IEventDrivenHealthCheck[] checks;