feat: add embedding-2 support for zhipu (#1273)

* 增加对智谱embedding-2模型的支持

* fix: fix usage & ratio

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Co-authored-by: yangfei <yangfei@xuyao.info>
Co-authored-by: JustSong <songquanpeng@foxmail.com>

relay/channel/zhipu/constants.go

@@ -2,5 +2,5 @@ package zhipu
 
 var ModelList = []string{
 	"chatglm_turbo", "chatglm_pro", "chatglm_std", "chatglm_lite",
-	"glm-4", "glm-4v", "glm-3-turbo",
+	"glm-4", "glm-4v", "glm-3-turbo", "embedding-2",
 }