Page 7 - Modifying SimpleViewModel causes Solution2 and Solution3 to crash the app/build

[Mario-paul]

On page 7 we modify popularity from type Popularity to LiveData<Popularity>, which causes the build to fail because the PlainOldActivitySolution2 and 3 depend on the older type. The solution ViewModels should connect to a separate solution PlainOldActivity that we do not touch, thereby preventing the issue.