Bump NUnit from 3.14.0 to 4.4.0

---
updated-dependencies:
- dependency-name: NUnit
  dependency-version: 4.4.0
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: NUnit
  dependency-version: 4.4.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

EchoServerTests/EchoServerTests.csproj

@@ -14,7 +14,7 @@
     <PackageReference Include="coverlet.msbuild" Version="6.0.4" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.4.0" />
     <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="5.2.0" />
   </ItemGroup>

NetSdrClientAppTests/NetSdrClientAppTests.csproj

@@ -17,7 +17,7 @@
 		</PackageReference>
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
 		<PackageReference Include="Moq" Version="4.20.72" />
-		<PackageReference Include="NUnit" Version="3.14.0" />
+		<PackageReference Include="NUnit" Version="4.4.0" />
 		<PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
 		<PackageReference Include="NUnit3TestAdapter" Version="5.2.0" />
 	</ItemGroup>