Crash when short_message misstype

[0LEG0]

Failed to send short_message 123 (number)

Here is my fix:
#228

Best regards, Anton

[fdciabdul]

Fixed in the maintained TypeScript fork node-smpp-next. The message encode filter now tolerates a non-string short_message (number / null / undefined) instead of throwing — same root cause as #256.
Fork: https://github.com/fdciabdul/node-smpp-next · npm: npm i node-smpp-next