Hide email settings on Sandstorm (#6429)

.sandstorm/launcher.sh

@@ -4,4 +4,5 @@ set -euvo pipefail
 
 export METEOR_SETTINGS='{"public": {"sandstorm": true}}'
 export NODE_ENV=production
+export SETTINGS_HIDDEN="Email,Email_Header,Email_Footer,SMTP_Host,SMTP_Port,SMTP_Username,SMTP_Password,From_Email,SMTP_Test_Button,Invitation_Customized,Invitation_Subject,Invitation_HTML,Accounts_Enrollment_Customized,Accounts_Enrollment_Email_Subject,Accounts_Enrollment_Email,Accounts_UserAddedEmail_Customized,Accounts_UserAddedEmailSubject,Accounts_UserAddedEmail,Forgot_Password_Customized,Forgot_Password_Email_Subject,Forgot_Password_Email,Verification_Customized,Verification_Email_Subject,Verification_Email"
 exec node /start.js -p 8000