GHSA-fm76-w8jw-xf8m: @saltcorn/plugins-loader unsanitized plugin name leads to a remote code execution (RCE) vulnerability when creating plugins using git source

When creating a new plugin using the git source, the user-controlled value req.body.name is used to build the plugin directory where the location will be cloned. The API used to execute the git clone command with the user-controlled data is child_process.execSync. Since the user-controlled data is not validated, a user with admin permission can add escaping characters and execute arbitrary commands, leading to a command injection vulnerability.