bugfix: project list broke when no companies were available

frontend/src/routes/project/List.svelte

@@ -89,7 +89,7 @@
                     {project.name}
                 </td>
                 <td class="company" onclick={() => show(project.id)} >
-                    {#if project.company_id}
+                    {#if project.company_id && companies[project.company_id]}
                     {companies[project.company_id].name}
                     {/if}
                 </td>