Fix escaped backtick syntax error in EmailBuilder.mjs

sed substitution literal-escaped the backtick and \${ in the
groupSSOReauthenticate subject line, producing invalid JS.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/web/app/src/Features/Email/EmailBuilder.mjs

@@ -517,7 +517,7 @@ templates.groupSSOLinkingInvite = ctaTemplate({
 
 templates.groupSSOReauthenticate = ctaTemplate({
   subject(opts) {
-    return \`Action required: Reauthenticate your \${settings.appName} account\`
+    return `Action required: Reauthenticate your ${settings.appName} account`
   },
   title(opts) {
     return 'Action required: Reauthenticate SSO'