feat: 优化

app/src/main/java/io/legado/app/help/http/HttpHelper.kt

@@ -43,7 +43,11 @@ object HttpHelper {
             val response = getApiService<HttpGetApi>(baseUrl, encode)
                 .get(url, mapOf())
                 .execute()
-            return response.body()
+            return if (response.body() != null) {
+                response.body()
+            } else {
+                response.errorBody().toString()
+            }
         }
         return null
     }