fix: getNodeWarning always returns warning
fix: getNodeWarning always returns warning

`getNodeWarning` always returns a warning, even when there's no such. It returns object with empty message, when it has to return null.

NativeScript/nativescript-cli,NathanaelA/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli