Updating package.json platform versions, doesn't work.

Environment

• CLI: 7.x

Describe the bug
Basically because we are using NPM now to manage the dependancies; it will store a copy of the runtime in @nativescript/ios or @nativescript/android if you bump the version of the package.json file; it will bump those copies; but the copy that we create in the "platforms/ios" or "platforms/android" remains whatever was their before.

Expected behavior
That I would have the version in the package.json file.

Additional context
We might need a post install script to clean the platforms/ios or platforms/android folder on install of the runtimes, so that way the next tns command will see the platforms folder empty and re-install the platforms from the npm version that was installed.

Possible corner case is if the CLI installs the platforms version before doing a npm i; we need to verify this isn't the case.

Empieza por rastrear cómo package.json actualiza las copias de runtime en @nativescript/ios y @nativescript/android, y después compáralo con el manejo existente de platforms/ios y platforms/android. Verifica si la CLI instala las plataformas antes de npm i y evalúa la limpieza posterior a la instalación propuesta. Se considera terminado cuando las carpetas de las plataformas usan las versiones instaladas desde package.json.