fix: drop container of MulimodalInput

Author: Col0ring

.changeset/great-places-post.md

@@ -0,0 +1,6 @@
+---
+'@modelscope-studio/pro': patch
+'modelscope_studio': patch
+---
+
+fix: drop container of MulimodalInput

frontend/pro/multimodal-input/multimodal-input.tsx

@@ -392,9 +392,13 @@ export const MultimodalInput = sveltify<
                     ...uploadConfig?.imageProps,
                   }}
                   disabled={uploadDisabled}
-                  getDropContainer={() => {
-                    return uploadConfig?.fullscreenDrop ? document.body : null;
-                  }}
+                  getDropContainer={
+                    uploadConfig?.fullscreenDrop
+                      ? () => {
+                          return document.body;
+                        }
+                      : undefined
+                  }
                   items={validFileList}
                   placeholder={(type) => {
                     const isDrop = type === 'drop';