Allow adding to platform composer.json and remove from direcotry

Problem/Motivation

I have a platform
the platform has composer.json
I add "drupal/h5p":"2@alpha"
I also include
"h5p/h5p-editor":"1.25",
"h5p/h5p-core":"1.27",

But h5p is not read from the platform wide vendor file like all of the other modules

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes