Add basic iOS and Android tests to example-app

[oskarth]

Problem

Currently in https://github.com/oskarth/mopro/tree/main/templates/mopro-example-app we don't have UI tests as we did in https://github.com/oskarth/mopro/tree/main/mopro-ios and https://github.com/oskarth/mopro/tree/main/mopro-android

It'd be nice to add them.

This then leads to us being able to use these examples for CI: https://github.com/oskarth/mopro/issues/117