Unconventional Youtube iframe src causes simple_amp module to break with video_filter

When a video filter code is included in a node, the simple_amp module does substitution on the resulting Youtube video code. Unfortunately it seems the code is concatenating URL query parameters with the HTML "&" which greatly confuses the simple_amp module's plugin.

DOMException: Invalid Character Error in DOMElement->setAttribute() (line 509 of .../vendor/querypath/querypath/src/QueryPath/DOMQuery.php).
QueryPath\DOMQuery->attr('data-param-amp;html5', '1') (Line: 174)

I propose we just implode with the regular ampersand character instead of "&". I don't think this would be a security issue, but would want some review.