Make sure input has correct format in generateCTXEnvironment

[bboldi]

I ran into some cases where input was undefined, and ionic run failed with TypeError: Cannot convert undefined or null to object , I propose making sure that input will not break the build process if there's something wrong with json config that it uses values from to run hooks.

[bboldi]

Did I miss something? Do I need to do anything else to get this reviewed? Thanks!