Fix: set folder info data project name column is nullable

src/main/java/com/example/kdan_data_center/datacenter/folder/data/FolderInfoData.kt

@@ -36,7 +36,7 @@ data class FolderInfoData(
                 @SerializedName("size") val size: Long,
                 @SerializedName("created_at") val createdAt: String,
                 @SerializedName("updated_at") val updatedAt: String,
-                @SerializedName("project_name") val projectName: String,
+                @SerializedName("project_name") val projectName: String?,
                 @SerializedName("project_created_at") val projectCreatedAt: String?,
                 @SerializedName("version") val version: Long?,
                 @SerializedName("cover_name") val coverName: String?,