fix: seedance only one text

relay/channel/task/doubao/adaptor.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"github.com/pkg/errors"
+	"github.com/samber/lo"
 )
 
 // ============================
@@ -241,13 +242,11 @@ func (a *TaskAdaptor) convertToRequestPayload(req *relaycommon.TaskSubmitReq) (*
 		return nil, errors.Wrap(err, "unmarshal metadata failed")
 	}
 
-	// Add text prompt
-	if req.Prompt != "" {
+	r.Content = lo.Reject(r.Content, func(c ContentItem, _ int) bool { return c.Type == "text" })
 	r.Content = append(r.Content, ContentItem{
 		Type: "text",
 		Text: req.Prompt,
 	})
-	}
 
 	return &r, nil
 }