Fix check isAndroidHomeValid
Fix check isAndroidHomeValid

The method that validates ANDROID_HOME returns array with errors, so current `if(isAndroidHomeValid)` checks are always true.
Create new method that returns boolean value and use it instead.

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