Bump Newtonsoft.Json from 13.0.3 to 13.0.4

---
updated-dependencies:
- dependency-name: Newtonsoft.Json
  dependency-version: 13.0.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

backend/backend.csproj

@@ -13,7 +13,7 @@
     </PackageReference>
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.0" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="10.0.1" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
     <PackageReference Include="DotNetEnv" Version="3.1.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="xunit" Version="2.9.3" />