fix: Add placeholder space for last feature chart tooltip

Author: techniq

frontend/src/routes/joins/[slug]/observability/drift/+page.svelte

@@ -18,6 +18,7 @@
 	import FeaturesLineChart from '$lib/components/charts/FeaturesLineChart.svelte';
 	import PercentileLineChart from '$lib/components/charts/PercentileLineChart.svelte';
 	import { barChartProps, pieChartProps, tooltipProps } from '$lib/components/charts/common';
+	import { cn } from '$src/lib/utils';
 
 	const api = new Api();
 
@@ -187,14 +188,19 @@
 		<ObservabilityNavTabs />
 
 		<div>
-			{#each data.joinTimeseries.items as group (group.name)}
+			{#each data.joinTimeseries.items as group, i (group.name)}
 				<CollapsibleSection
 					title={group.name}
 					size="small"
 					bind:open={groupSectionStates[group.name]}
 				>
 					{#snippet collapsibleContent()}
-						<div class="h-[274px]">
+						<div
+							class={cn(
+								'h-[274px]',
+								i === data.joinTimeseries.items.length - 1 && 'mb-[300px]' // Add extra space at bottom of page for tooltip
+							)}
+						>
 							<FeaturesLineChart
 								data={group.items}
 								yDomain={metricTypeDomain}