style: fix prefer-svelte-reactivity — replace with Svelte reactive equivalents

frontend/src/lib/components/admin/WalkInCreateModal.svelte

@@ -2,7 +2,7 @@
 	import { authStore } from '$lib/stores/auth.svelte';
 	import { generateUUID } from '$lib/utils/uuid';
 	import { toast } from 'svelte-sonner';
-	import { SvelteDate } from 'svelte/reactivity';
+	import { SvelteDate, SvelteURLSearchParams } from 'svelte/reactivity';
 	import { getLocalTimeZone } from '@internationalized/date';
 	import { isValidUKPhone, toE164UK } from '$lib/utils/phone';
 	import { formatUserName } from '$lib/utils/nameDisplay';
@@ -351,7 +351,7 @@
 	async function fetchCustomServices() {
 		loadingCustomServices = true;
 		try {
-			const params = new URLSearchParams();
+			const params = new SvelteURLSearchParams();
 			if (customSearchQuery.trim()) {
 				params.set('q', customSearchQuery.trim());
 			} else {