fix(fm): prevent dragging detail thumbnails and avatars into upload zones (#3176)

Native img drags from the file-detail sidebar and user avatars were
treated as file drops by the upload zone. Explorer thumbnails already
suppress native dragging; apply the same to both.

frontend/src/component/Common/User/UserAvatar.tsx

@@ -119,6 +119,7 @@ const UserAvatar = memo(
                 img: {
                   loading: "lazy",
                   alt: "",
+                  draggable: false,
                 },
               }}
               {...rest}

frontend/src/component/FileManager/Sidebar/Details.tsx

@@ -50,6 +50,7 @@ const Details = ({ target, inPhotoViewer, setTarget, targetDisplayOptions }: Det
             setThumbSrc(null);
           }}
           src={thumbSrc}
+          draggable={false}
           sx={{
             borderRadius: "8px",
           }}