chore: add error handling for appimagetool download

Author: Minh141120

src-tauri/build-utils/buildAppImage.sh

@@ -3,7 +3,7 @@ APPIMAGETOOL="./.cache/build-tools/appimagetool"
 RELEASE_CHANNEL=${RELEASE_CHANNEL:-"stable"}
 
 mkdir -p ./.cache/build-tools
-wget https://github.com/AppImage/appimagetool/releases/download/continuous/appimagetool-x86_64.AppImage -O "${APPIMAGETOOL}"
+wget https://github.com/AppImage/appimagetool/releases/download/continuous/appimagetool-x86_64.AppImage -O "${APPIMAGETOOL}" || { echo "Failed to download appimagetool."; exit 1; }
 chmod +x "${APPIMAGETOOL}"
 
 if [ "${RELEASE_CHANNEL}" != "stable" ]; then