Use AFRAME.utils.split in getComponentPropertyPath fixing caching behaviour

[mrxz]

Description:
Noticed that that AFRAME.utils.entity.getComponentPropertyPath didn't properly use its cache. It constructed a cache and populated it, but never checked if strings were already cached. Meaning it would always recompute (= split), place in cache and then immediately return that value from the cache.

This PR simply replaces the broken caching mechanism with AFRAME.utils.split, since the split utility also uses a cache internally. Added benefit is that the cache is now also shared between the two.

Changes proposed:

• Fix property path caching by using AFRAME.utils.split which internally caches

[dmarcos]

Thanks!