Adding "page_speed_X" attribute breaks class attribute for AlpineJS

[Pixel-Tony]

🔎 Context
When using the package, classes of type page_speed_... are added to the start of relevant elements, but in doing so, class attribute is being replaced by :class. This breaks AlpineJS, as it recognises resulting :class as an x-bind directive, which it obviously isn't. Also, the original :class attribute is replaced if present.

🔢 Steps to reproduce

1. Enable usage of the package in the project.
2. Use class attribute on element inside other element containing x-data.
3. Try to enter the page.

👍 Expected behaviour
class attribute will only get page_speed_... appended to it, enabling speed-up.

👎 Resulting behaviour
class attribute C is replaced with :class one, removing both original C and correct :class one if present.