Bump HotChocolate.AspNetCore from 14.3.0 to 15.1.15

---
updated-dependencies:
- dependency-name: HotChocolate.AspNetCore
  dependency-version: 15.1.15
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]

src/HotChocolateGraphQL.Backend/HotChocolateGraphQL.Backend.csproj

@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="HotChocolate.AspNetCore" Version="14.3.0" />
+    <PackageReference Include="HotChocolate.AspNetCore" Version="15.1.15" />
     <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="9.0.0" />
   </ItemGroup>