fix: [Orchestration] Remove @Beta from OrchestrationSpringEmbeddingModel

[rpanackal]

Context

AI/ai-sdk-java-backlog#ISSUENUMBER.

OrchestrationSpringEmbeddingModel was release as Beta, simply to gracefully accommodate any unforeseen breaking changes.

Since, no beta objects are in public api contract, its now marked stable.

Definition of Done

• Functionality scope stated & covered
• Tests cover the scope above
• Error handling created / updated & covered by the tests above
• Aligned changes with the JavaScript SDK
• Documentation updated
• Release notes updated

[MatKuhr]

what about related classes e.g https://github.com/SAP/ai-sdk-java/blob/main/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationEmbeddingRequest.java ?

[rpanackal]

what about related classes e.g https://github.com/SAP/ai-sdk-java/blob/main/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationEmbeddingRequest.java ?

This needs some work before It can be marked stable.

I left this as @Beta since

• we only support float response encoding format (also affect the related OrchestrationEmbeddingResponse).Maybe this is fine since we received no user request for base64 and binary types.
• we couldn't test the available models inOrchestrationEmbeddingModel via scenario tests. The model list api was very out of sync at the time.