fix: Fixed favourites to not show up when a user hasn't been logged in

Co-Authored-By: Tadios Temesgen <tt2022@ic.ac.uk>

src/lib/components/SpaceCard.svelte

@@ -11,7 +11,8 @@
         imgSrc: string;
         href?: string;
         isFavourite: boolean;
-        onToggleFavourite: () => void;
+
+        onToggleFavourite?: () => void;
     }
 
     const { space, hours, alt, imgSrc, href, isFavourite, onToggleFavourite }: Props = $props();
@@ -21,9 +22,11 @@
     <!-- <img src={imgSrc} {alt} /> -->
     <div class="image-container">
         <img src={imgSrc} {alt} />
-        <div class="fav-button">
-            <Favourite {isFavourite} {onToggleFavourite} />
-        </div>
+        {#if onToggleFavourite}
+            <div class="fav-button">
+                <Favourite {isFavourite} {onToggleFavourite} />
+            </div>
+        {/if}
     </div>
     <div class="description">
         <h1>{space.location}</h1>