H5P settings not always available in iframe

I'll take a look at this issue. I'm not sure yet what the solution is, but I'm familiar with the problem from working on 🐛 D11 Console Errors Active

OK, I've got a fix for this and will push to the issue branch shortly. There were a few things going on:

• Drupal core and H5P core libraries were getting added to the aggregation that didn't need to be there.
• Excluding the `h5p.content` library solved this, but errors were still appearing in the console.
• Turning off aggregation resolved those errors.
• I don't fully understand this, but think it's a good idea anyway because this seems to be what the h5p.js init code for iframes is expecting./li>
• ...further, I've seen cases where specific H5P libraries inspect this array (see: https://github.com/otacke/h5p-game-map/blob/f8631762f36d794823ee296d92b5...).

This is ready for review.