electron-updater: Uncontrolled search path elements within `AppImage` built by `app-builder-lib`

electron-updater allows for automatic updates for Electron apps. Prior to 26.15.0, AppImage targets built by app-builder-lib could use an empty path component when setting the LD_LIBRARY_PATH environment variable at runtime. This causes the current working directory to be added to the dynamic linker search path, which may allow an attacker to execute arbitrary code by placing a malicious shared library in the directory from which the AppImage is launched. This issue has been fixed in version 26.15.0.