When Mozilla let their intermediate signing certificate expire, it affected addons in the normal Firefox browser. This caused the NoScript and HTTPS-Everywhere addons to no longer work in the Tor browser. As a temporary fix, you can disable this signature requirement by setting the xpinstall.signatures.required setting to false. Tor will only be disabled until Tor releases a new version with a bundled fix. This warning will go away when the new version of Tor is released with the fix.
Source: https://www.bleepingcomputer.com/news/security/fix-for-tor-browser-noscript-addon-being-disabled/