Remove some old and unreachable code (#804)

code/backend/Cleanuparr.Infrastructure/Http/DynamicHttpClientSystem/IHttpClientConfigStore.cs

@@ -20,11 +20,6 @@ public interface IHttpClientConfigStore
     /// </summary>
     void RemoveConfiguration(string clientName);
     
-    /// <summary>
-    /// Adds or updates a retry configuration for the specified client name
-    /// </summary>
-    void AddRetryConfiguration(string clientName, RetryConfig retryConfig);
-    
     /// <summary>
     /// Gets all currently registered configurations
     /// </summary>