Bump nunit from 4.3.0 to 4.3.1 in /src (#2751)

Bumps [nunit](https://github.com/nunit/nunit) from 4.3.0 to 4.3.1.
- [Release notes](https://github.com/nunit/nunit/releases)
- [Changelog](https://github.com/nunit/nunit/blob/main/CHANGES.md)
- [Commits](nunit/nunit@4.3.0...4.3.1)

---
updated-dependencies:
- dependency-name: nunit
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Core/NUnitTestCore/NUnitTestCore.csproj

@@ -91,7 +91,7 @@
     <EmbeddedResource Include="..\..\Nupkg\ErikEJ.EntityFrameworkCore.DgmlBuilder\template.dgml" Link="template.dgml" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="nunit" Version="4.3.0" />
+    <PackageReference Include="nunit" Version="4.3.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <!-- Updated due to vulnerable 4.3.0 package -->

src/GUI/UnitTests/UnitTests.csproj

@@ -101,7 +101,7 @@
       <Version>5.4.1.1</Version>
     </PackageReference>
     <PackageReference Include="NUnit">
-      <Version>4.3.0</Version>
+      <Version>4.3.1</Version>
     </PackageReference>
     <PackageReference Include="NUnit3TestAdapter">
       <Version>4.6.0</Version>