Issue #3526331: Fix to allow multiple H5P CSS/JS alter files
Problem
In a 2.0.0-alpha5, the ability to alter CSS/JS for H5P nodes was inadvertently removed. A subsequent fix re-added this feature, but it only worked for the first custom JS or CSS file added via the alter hook.
Solution
This fix allows for multiple CSS/JS files to be added via the alter hooks.
Closes #3526331