fix(tooling): non-existent collection in property delegates

Author: matkoch

source/Nuke.Common.Tests/SettingsTest.cs

@@ -126,6 +126,28 @@ public void TestDotNet()
             "pack --property:Authors=a,b");
     }
 
+    [Fact]
+    public void TestDotNet_Delegate()
+    {
+        Assert(new DotNetBuildSettings()
+                .SetNoWarns(1337),
+            "build --property:NoWarn=1337");
+
+        Assert(new DotNetBuildSettings()
+                .SetNoWarns(1337, 555)
+                .RemoveNoWarns(555),
+            "build --property:NoWarn=1337");
+
+        Assert(new DotNetBuildSettings()
+                .AddNoWarns(1337),
+            "build --property:NoWarn=1337");
+
+        Assert(new DotNetBuildSettings()
+                .AddNoWarns(1337)
+                .SetNoWarns(555),
+            "build --property:NoWarn=555");
+    }
+
     [Fact]
     public void TestDotNet_Empty()
     {

source/Nuke.Tooling/DelegateHelper.cs

@@ -55,14 +55,14 @@ public static IDictionary<string, object> RemoveCollection<TValue>(
         var newDictionary = dictionary?.ToDictionary(x => x.Key, x => x.Value) ?? new Dictionary<string, object>();
         var valueHashSet = new HashSet<TValue>(values);
         var collection = ParseCollection<TValue>(dictionary, key, separator);
-        collection.RemoveAll(x => valueHashSet.Contains((TValue)x));
+        collection.RemoveAll(x => valueHashSet.Contains(x));
         newDictionary[key] = CollectionToString(collection, separator);
         return newDictionary;
     }
 
     private static List<TValue> ParseCollection<TValue>(IReadOnlyDictionary<string, object> dictionary, string key, string separator)
     {
-        return (dictionary.TryGetValue(key, out var value)
+        return (dictionary?.TryGetValue(key, out var value) ?? false
                 ? ((string)value).Split([separator], StringSplitOptions.RemoveEmptyEntries)
                 : [])
             .Select(ReflectionUtility.Convert<TValue>).ToList();