Adjust the UnitTests project to comply with new WarnThatFinalizerIsReached checks

Source/QuestPDF.UnitTests/ImageTests.cs

@@ -109,12 +109,12 @@ namespace QuestPDF.UnitTests
                 });
             });
 
+            using var sharedImage = DocumentImage.FromBinaryData(photo);
+            
             var documentWithSingleImageUsedMultipleTimesSize = GetDocumentSize(container =>
             {
                 container.Column(column =>
                 {
-                    var sharedImage = DocumentImage.FromBinaryData(photo);
-                    
                     foreach (var i in Enumerable.Range(0, 10))
                         column.Item().Image(sharedImage);
                 });

Source/QuestPDF.UnitTests/QuestPDF.UnitTests.csproj

@@ -8,7 +8,7 @@
 
     <ItemGroup>
         <PackageReference Include="FluentAssertions" Version="6.12.1" />
-        <PackageReference Include="nunit" Version="4.2.2" />
+        <PackageReference Include="nunit" Version="4.3.2" />
         <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
         <PackageReference Include="SkiaSharp" Version="3.116.1" />

Source/QuestPDF.UnitTests/TestEngine/TestPlan.cs

@@ -200,6 +200,7 @@ namespace QuestPDF.UnitTests.TestEngine
             Element.InjectDependencies(null, Canvas);
             
             var actual = Element.Measure(OperationInput);
+            Element.ReleaseDisposableChildren();
             
             ClassicAssert.AreEqual(expected.GetType(), actual.GetType());
             
@@ -215,6 +216,7 @@ namespace QuestPDF.UnitTests.TestEngine
         {
             Element.InjectDependencies(null, Canvas);
             Element.Draw(OperationInput);
+            Element.ReleaseDisposableChildren();
             return this;
         }