Sending x-api-key instead of api-key as header for azure hosted anthropic service (#11517)

* Fix for sending x-api-key instead of api-key as header for newer azure hosted anthropic service

* Update packages/openai-adapters/src/apis/AnthropicUtils.ts

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

* fix: update test to expect x-api-key for Azure AI Foundry endpoints

Azure AI Foundry (services.ai.azure.com) uses x-api-key, while only
cognitiveservices.azure.com uses api-key. Update the test to match.

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Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>
Co-authored-by: Dallin Romney <dallinromney@gmail.com>