Keep the carousel label white over its scrim

The scrim is --md-sys-color-scrim, black in every scheme, theme and contrast level,
so the ink over it is the absolute the theme keeps rather than inverse-on-surface,
which is dark in a dark scheme (containment C-25, revisited).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Feature/Components/CarouselTest.php

@@ -151,7 +151,7 @@ it('lays a label over an item on a scrim, and passes attributes to the item', fu
         ->toContain('data-material-carousel-label')
         ->toContain('Lake Constance')
         ->toContain('from-scrim/60')
-        ->toContain('type-title-md text-inverse-on-surface')
+        ->toContain('type-title-md text-white')
         ->toContain('[&>img]:size-full [&>img]:object-cover')
         ->and((string) $this->blade('<x-carousel-item>A</x-carousel-item>'))
         ->not->toContain('data-material-carousel-label');