…pletionsConversionTrait

…ts (guillaume-ro-fr)

This PR was squashed before being merged into the main branch.

Discussion
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[Platform][Generic][Scaleway] Fix tool call without arguments

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Docs?         | no <!-- required for new features -->
| Issues        | None <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT

When calling a tool on Scaleway (extends Generic, the `arguments` array may not be included in the results, which causes problems when converting the result with `ResultConverter`.

This PR fixes the issue by checking that the array exists before retrieving its content.

Linked to #1649 (closed - merge conflicts)

Commits
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59601c0b [Platform][Generic][Scaleway] Fix tool call without arguments

… deltas

Add TokenUsageExtractor for embeddings in OpenAi, Generic, Scaleway,
DockerModelRunner and VertexAi bridges.

The extractors parse token usage information from embedding API responses
and return a TokenUsage object with prompt and total token counts.

VertexAi uses a different response format with per-embedding statistics,
so the extractor sums up token_count from all predictions.