chore: disable loop prevention protection

Author: Candinya

src/handler/download.rs

@@ -26,6 +26,13 @@ pub async fn download_image<'a>(
     }
 
     // Check if UserAgent is valid
+    /*
+     * todo: this protection is temporarily disabled
+     *     because Misskey will hard-code media-proxy url to user's avatarUrl field,
+     *     which will definitely cause a recursive loop when media-proxy is enabled.
+     *     This feature should be re-enabled once this situation is resolved and
+     *     database all updated (or some old user may still facing broken image error).
+
     if let Some(ua) = ua {
         if ua.to_lowercase().contains("misskey/") || ua.to_lowercase().contains("misskeymediaproxy")
         {
@@ -35,6 +42,8 @@ pub async fn download_image<'a>(
         }
     }
 
+     */
+
     // Start download
     let url = url.unwrap();
     let downloaded_file = match downloader.download_file(url, host).await {