Refactor Mihomo proxy groups component for improved styling and accessibility

- Simplified the layout of compact mode in the MihomoProxyGroups component by removing unnecessary styling elements.
- Enhanced the accessibility of group elements by maintaining essential ARIA attributes while streamlining the overall structure.
- Improved readability and user experience through cleaner code and layout adjustments.

web/src/lib/components/mihomo/mihomo-proxy-groups.svelte

@@ -227,11 +227,7 @@
 			<div class={cn('flex flex-col', compact ? 'gap-2' : 'gap-8')}>
 				{#each selectableGroups as [gName, group] (gName)}
 					{#if compact}
-						<div
-							class="bg-muted/15 space-y-2 rounded-md border border-border/50 p-2 sm:p-2.5"
-							role="group"
-							aria-label="Группа {gName}"
-						>
+						<div class="space-y-2" role="group" aria-label="Группа {gName}">
 							<div class="flex flex-wrap items-center gap-2">
 								<div class="flex min-w-0 flex-1 flex-wrap items-center gap-x-2 gap-y-1">
 									<Badge variant="outline" class="h-5 px-1.5 font-mono text-[10px] uppercase tracking-wide">