OpenAI: Add Usage to `v1/embeddings` (#5886)

* add prompt tokens to embed response

* rm slog

* metrics

* types

* prompt n

* clean up

* reset submodule

* add tokens to v1/embeddings

* separate usage

openai/openai.go

@@ -167,6 +167,12 @@ type EmbeddingList struct {
 	Object string         `json:"object"`
 	Data   []Embedding    `json:"data"`
 	Model  string         `json:"model"`
+	Usage  EmbeddingUsage `json:"usage,omitempty"`
+}
+
+type EmbeddingUsage struct {
+	PromptTokens int `json:"prompt_tokens"`
+	TotalTokens  int `json:"total_tokens"`
 }
 
 func NewError(code int, message string) ErrorResponse {
@@ -332,6 +338,10 @@ func toEmbeddingList(model string, r api.EmbedResponse) EmbeddingList {
 			Object: "list",
 			Data:   data,
 			Model:  model,
+			Usage: EmbeddingUsage{
+				PromptTokens: r.PromptEvalCount,
+				TotalTokens:  r.PromptEvalCount,
+			},
 		}
 	}