feat: metadata correct parse

relay/common/relay_utils.go

@@ -204,7 +204,9 @@ func ValidateBasicTaskRequest(c *gin.Context, info *RelayInfo, action string) *d
 		if err != nil {
 			return createTaskError(err, "invalid_multipart_form", http.StatusBadRequest, true)
 		}
-	} else if err := common.UnmarshalBodyReusable(c, &req); err != nil {
+	}
+	// 为了metadata字段的兼容性，统一UnmarshalBodyReusable
+	if err := common.UnmarshalBodyReusable(c, &req); err != nil {
 		return createTaskError(err, "invalid_request", http.StatusBadRequest, true)
 	}