New: (Cardigann) Add AllowEmptyInputs

Co-Authored-By: Bogdan <mynameisbogdan@users.noreply.github.com>

src/NzbDrone.Core/Indexers/Definitions/Cardigann/CardigannDefinition.cs

@@ -144,6 +144,7 @@ namespace NzbDrone.Core.Indexers.Cardigann
     {
         public int PageSize { get; set; }
         public int FirstPageNumber { get; set; }
+        public bool AllowEmptyInputs { get; set; }
         public string Path { get; set; }
         public List<SearchPathBlock> Paths { get; set; }
         public Dictionary<string, List<string>> Headers { get; set; }

src/NzbDrone.Core/Indexers/Definitions/Cardigann/CardigannRequestGenerator.cs

@@ -1117,7 +1117,12 @@ namespace NzbDrone.Core.Indexers.Cardigann
                                 }
                                 else
                                 {
-                                    queryCollection.Add(input.Key, ApplyGoTemplateText(input.Value, variables));
+                                    var inputValue = ApplyGoTemplateText(input.Value, variables);
+
+                                    if (!string.IsNullOrWhiteSpace(inputValue) || search.AllowEmptyInputs)
+                                    {
+                                        queryCollection.Add(input.Key, inputValue);
+                                    }
                                 }
                             }
                         }