Paragraphs module compatibility

#2 was not quite enough. The problem with the Paragraphs use seems to be that the H5P module expects the field name to be unique, and that's not the case if H5P is a paragraph type. This patch should fix it.

This one also contains an idea from 📌 Indication of uploaded .h5p file RTBC , but it didn't quite work standalone without this one either.

This patch still applies as of the release of 2.0.0-alpha6, and seems to fix the problem indicated. I did a bit of testing using the H5P file upload widget within a paragraph and also in a standard node, using single and mulit-value fields. Everything I tried worked. Marking RTBC.

Created a MR and tried to copy over all the changes from the patch file. I'll double-check that they look the same before merging.

Great! Thanks, all! Merged and marking as fixed.