fix: prompt calculation

User will correctly get estimated prompt usage when upstream returns either zero or nothing.

controller/relay.go

@@ -128,6 +128,8 @@ func Relay(c *gin.Context, relayFormat types.RelayFormat) {
 		return
 	}
 
+	relayInfo.SetPromptTokens(tokens)
+
 	priceData, err := helper.ModelPriceHelper(c, relayInfo, tokens, meta)
 	if err != nil {
 		newAPIError = types.NewError(err, types.ErrorCodeModelPriceError)