Improve logic in compute_style_properties to improve performance. This commit fixes a number of performance issues including.

- Expensive repeated call to `str_starts_with`.
- Return easy if not array.
- Repeated call to `strlen`.
- Move call to `get_property_value` where it is needed.
- Move call to implode to after empty check.

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>