Appc new should be more cautious when unable to read Ti activeSDK value

When appc new failed to retrieve active Ti SDK version, following error occurred with the command appc new

ERROR  | Cannot read property 'split' of undefined

Reproduce steps

1. appc use 5.1.0
2. remove/rename .titanium/config.json
3. remove/rename Application Support/Titanium/mobilesdk
4. appc new

Expected result

you should see the following prompt instead of the undefined error

? What type of project are you creating? (Use arrow keys)

❯ Native App 

  Arrow App 

  Titanium Module 

Actual result

Project type selection prompt is not shown, and process errors out:
ERROR | Cannot read property 'split' of undefined