Fixes#17520
Fixes multi-value inset shadows to apply the `inset` prefix to each
component instead of only the first.
Feel free to make the code nicer 😄
## Test plan
Ensure that a multi-value inset shadow now applies each shadow _inset_:
<img width="505" alt="Screenshot 2025-04-03 at 10 50 29"
src="https://github.com/user-attachments/assets/5d38de45-a16f-48fd-8e3c-b50d2740eb49"
/>
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Co-authored-by: Philipp Spiess <hello@philippspiess.com>
80f9578bfa