Add missing gherkin tests

[askpt]

Description

We are only running the gherkin tests against the evaluation.feature file. We must ensure that we are also testing against hooks.feature and metadata.feature.
As a small investigation, we should make sure to copy the required feature files during the build of project OpenFeature.E2ETests.csproj.

Notes

• Files can be found here: https://github.com/open-feature/spec/tree/main/specification/assets/gherkin
• The project where we need to add the tests: https://github.com/open-feature/dotnet-sdk/tree/main/test/OpenFeature.E2ETests
• Workflow needs to be updated to copy the feature files https://github.com/open-feature/dotnet-sdk/blob/main/.github/workflows/e2e.yml