IBX-11397: Added resolving embedding provider by model identifier for taxonomy embeddings

[mikadamczyk]

🎫 Issue	IBX-11397

Description:

This PR extends EmbeddingProviderResolverInterface with a new method resolveByModelIdentifier(string $modelIdentifier): EmbeddingProviderInterface and adds its implementation in Ibexa\Core\Search\Embedding\EmbeddingProviderResolver. Now EmbeddingProviderResolver::resolve() always resolves the provider from the global default embedding model default_embedding_model.
This becomes problematic when a feature uses a different embedding model than the global default, for example taxonomy embeddings configured via: taxonomy.search.default_embedding_model

In such a case, the caller may pass a model name for Gemini, but the resolver still returns the provider from the global default model (for example, OpenAI), which leads to mismatched provider and model combinations and runtime failures.

This change enables callers to resolve an embedding provider using the provider configured for a specific embedding model identifier, from embedding_models, instead of relying on the global default provider. This is especially needed for taxonomy embeddings, where model selection can be overridden independently from the global default embedding model.

This API is introduced to be used by consumers that operate on a specific embedding model configuration (taxonomy embedding generation), so they can resolve the correct provider in a deterministic way:
model identifier -> embedding_models[<id>].embedding_provider -> provider instance

Existing callers using resolve() are unaffected. The new method is additive and intended for cases where the embedding model differs from the global default

This method will be used in taxonomy embedding generation to resolve the provider based on taxonomy.search.default_embedding_model, avoiding provider and model mismatch when taxonomy embeddings use a non-default provider (e.g., Gemini).

For QA:

Documentation:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[alongosz]

Merging to unblock ibexa/taxonomy#396.