Fix TypeError on `isCSSColorSchemePropSupported` (#8463)
Fix TypeError on `isCSSColorSchemePropSupported` (#8463)

- There's a chance that `el.style` can be undefined. We need to account
for that.
- Resolves #8368
alexanderby/darkreader,darkreader/darkreader,darkreader/darkreader,darkreader/darkreader,alexanderby/darkreader,alexanderby/darkreader